KANSAS CITY, Mo. — Brawny pickups and SUVs sporting trailer hitch ball mounts and license plates from Kansas, Missouri and Oklahoma pack a scrubby rock courtyard behind a picture-postcard farmhouse in Louisburg, Kan. Around front, eight camping trailers stand stem to stern in tight formation facing the open doors of a two-story white barn. Extension cords have been laid, canopies staked, logs for the campfire cut and stacked, coolers and camp chairs arrayed in a circle. The sun hangs low in the west, and the campers are ready for a hard-earned happy hour. One by one they emerge from their trailers in cowboy boots and lace petticoats, floor-length gowns and mod '60s sheaths topped with fur stoles. They sip lemon drop martinis and snack on sliced Twinkies speared with toothpicks and crackers sprayed with canned Easy Cheese as Marvin Gaye wails "I Heard It Through the Grapevine" on a boom box. Fragrant pinion wood smolders in a tiny chiminea. The campers are women from the region who belong to Sisters on the Fly, a national group of camping enthusiasts founded by two actual sisters who love fly-fishing in Montana. The sisterhood has three rules: No husbands. No pets. Be nice. The founding sisters, Maurrie Sussman and Becky Clarke, have seen their sorority of adventurers grow from a dozen in 1999 to about1,700 active members today in all 50 states and Canada. "The idea was always to get women into the outdoors," Sussman says. National events draw up to 100 women to campgrounds and beaches across the continent, sometimes towing trailers in long caravans across interstate highways and scenic byways. National events last a week, and smaller regional "git-togethers," like this one in Louisburg, typically last three or four days. Sisters learn or practice skills such as fishing, shooting, kayaking, horseback riding, cattle-roping and cooking over a campfire. But playing cowgirl is only half the appeal to the women, ages 21 to 93, who make up Sisters on the Fly. At the Louisburg campsite, half an hour south of Kansas City, the parked posse of Oasis, Comet, Scotty and Forester trailers confirms that the sisterhood is as much about rescuing and personalizing classic trailers as it is about camping. The trailers are painted on all sides with bold, retro-looking graphics depicting cowgirls on the open range, horses, bikinis dangling from a clothesline strung between palm trees and oversized sunflowers. Each is emblazoned with a name: The Kansas Kid. Giddy Up Girl. Toto's Tin Can. Cowgirls in Paradise. Inside the trailers, most Sisters have preserved where possible original features such as wood siding, laminate dinette tables, gas stove/oven combos and electric lamps, while opening up the floor plans by removing closets and replacing convertible couches with full-size beds. They have also taken extreme liberties with decor. Inside Ramblin' Rose, curtains hang from garter straps. Faux logs glow inside a mock heater. A framed "license for prostitution" issued to one Midnight Rose and "signed" by Wyatt Earp hangs on the wall. Above the red-satin expanse of a bed hangs a painted wooden sign proclaiming "Just put on your big girl panties and deal with it." This open-road boudoir is one of four trailers owned by Karla Jones, a retired mounted policewoman from Broken Arrow, Okla. It is the most recent of 19 she has purchased since joining the Sisters in 2006. "She changes trailers like she changes underwear," a fellow Sister calls out. Sisters on the Fly has turned out to be a blessing for Jones' husband of 30 years, Guss, and not just because it gives them both some personal space. "He was looking for a hobby after he retired," she said. "Now he restores trailers." Sussman, the founding Sister who divides her time between Phoenix and Montana, says the uber-outfitting of the trailers comes down to comfort. "We enjoy dragging our bedrooms with us, so after a hard day of fishing and hiking we can sink into our own featherbeds." In that regard, Sisters on the Fly are reviving the dream that fueled the golden age of trailer travel in the 1930s through the 1960s: experiencing the great outdoors while bringing all the comforts of home with you. They are also rescuing and reviving the actual aluminum and wood trailers Americans pulled behind station wagons half a century ago, before cheap air travel allowed us to overfly the nation's great national parks and kitschy roadside attractions, author Irene Rawlings notes in "Sisters on the Fly: Caravans, Campfires and Tales From the Road" (Andrews McMeel; $15). As swelling strains of Paul Simon's "The Boxer" mask the occasional traffic on Kansas 68, several campers have changed out of cocktail attire into their normal get-ups of designer jeans, elaborately tooled Western boots in jewel tones, straw cowboy hats, fringed leather jackets and rhinestone headbands. They are carrying homemade foods from their tiny trailer kitchens into the barn for dinner: chicken enchiladas, cheesy potato soup, cowboy beans, clover rolls and sweet potato pie. Sharon Morrisey of Louisburg owns the farm where 12 women from three states have gathered on this late-April weekend. Morrisey and her husband, Tom, bought a 1970 Serro Scotty HiLander in 2006. The couple, who have three children and six grandchildren, picked up the trailer in Maryville, N.Y., after finding it online. "It was going to be me and Tom's trailer," Morrisey says. But she was intrigued by a line she had read in another online ad: "If you buy this trailer, you'll be the hit of Sisters on the Fly." When the couple got home after picking up their trailer, Morrisey Googled the organization (sistersonthefly.com) and told Tom about it. His reaction was, "That looks like fun. I think you should do it." She did, decorating her trailer with vintage linens depicting buxom cowgirls cavorting near streams and mountains, beaded lamps, decoupaged leather suitcases for storage and a blue-fringed valence decorated with covered wagons and wildflowers. "My grandmother made the valence. I take it so she can go with me," Morrisey says. She and Tom sometimes take her trailer, The Kansas Kid, to camp along the California coastline. But camping with the Sisters is totally different, she explains, leaning forward, her soft blue eyes widening just a bit. "You are responsible for everything, from hitching the trailer to towing it, including backing up. If you get a flat, you have to fix it." Well, except for that one time when a male motorist insisted on changing a flat tire for Morrisey when she was traveling with her daughter. When he was done, the man said, "God bless you, Sisters," and Morrisey realized he had seen the "Sisters on the Fly" logo on her trailer and thought they were nuns. "I said, 'And peace be with you,'" Morrisey recalls, laughing. Self-reliance has been the biggest reward for one of the newest members at the Louisburg campout, Lori Thompson of Leawood. In March 2011, Thompson, a Realtor, saw an article about Sisters on the Fly in Trailer Life magazine. "I was enchanted with them from the very beginning," she says. But not having a trailer held her back. Finally her husband, Vernon, told her, "Quit talking about it and join and then you'll find a trailer." Which is exactly what happened: Thompson bought a 1959 Oasis from a Sister who had acquired a 1984 Hi-Lo camper because she was ready to sacrifice cuteness for the convenience of a water pump, toilet and shower. Thompson grew up camping. Her parents had a truck camper. She and her two sisters slept in the bunk above the cab. "Our bathroom was a 5-pound coffee can, so not having a toilet is nothing new for me," she says. Since joining the Sisters, Thompson has learned kayaking, archery, fishing and Dutch oven cooking. And how to tow a trailer. "Sometimes my husband starts to hitch up the trailer and I say, 'I'll do it.' I can put the chains on and do the whole pre-towing safety check," she says. "I'm very pleased." Thompson hopes to learn how to shoot a gun one day, but this evening she has another first in mind. She ducks into her trailer, which is covered with painted sunflowers and a high-kicking-cowgirl version of Dorothy with Toto, and returns waving a plastic bag filled with honey-flavored cigars. "C'mon girls! Who wants to earn a smoking-a-cigar badge?" Thompson calls, flipping her shoulder-length blond hair out of the way of an enormous fireplace lighter. Three sisters take up the challenge, and there ensues a scene straight out of a Warner Bros. cartoon of women who obviously don't know how to smoke, trying to. After the briefest amount of puffing and coughing, the undertaking is declared a success, and the stogies extinguished. Sisters on the Fly does indeed have merit badges — 30 to date, with more added as members think them up. In addition to "Cigar Affectionado," there are "Camping in Bad Weather," "Going Potty Outside" and "Nymph," awarded for showering outdoors in your birthday suit. The badges, which Sisters sew onto sashes or denim jackets, are an obvious nod to Girl Scouts. Fond memories of Scouting are a common denominator for many members, Deb Gaskill says. Gaskill, a retired nuclear reactor tool room supervisor from Warsaw, Mo., says something else many Sisters have in common is an obsessive love of vintage trailers. She has bought two since joining the Sisters last year — a 1958 Mercury and a 1959 Cardinal. "It's a sickness. It starts out as such a romantic thing. It's like going for the brass ring. You buy this sweet thing and tow it home and then it's OMG," she says. "But they are so cool. They are over 50 years old, and you fantasize about them. You wonder: Where have you been?" Helen Elston of Cleaver, Mo., the ranking Sister at the Louisburg meet-up with the enviable Sister number of 99 (out of 2,540 assigned to date), bought her trailer shortly after her mother died in 2002. After the bills were paid, there was $400 left for each of the five siblings, but Elston couldn't bring herself to spend her mother's money. Then she saw an ad for a 1966 Comet near Springfield, Mo. "I thought, 'Bingo. Mom would have loved this,'" Elston says. "Then I called my son to help me get new wheels on it, and he thought I'd lost my mind." Her other two children agreed, especially when Elston towed her trailer to Hot Springs, Ark., to her first Sisters trip, not knowing a soul. "But when I left I knew everybody," she says. An informal storytelling circle is under way near the barn, and Elston takes the chair in the center of the ring. Her tiny hands hold a large, hand-sewn quilt with a patch in one corner that bears her name and the words "Lovingly Made for You by Sisters on the Fly." Elston explains that she was diagnosed with cancer in October and underwent four surgeries in eight weeks. Last week, on the day before her birthday, she says, a large box arrived in the mail. In it was the quilt, sent from founding Sister Maurrie Sussman. The quilt was accompanied by a note that said, in part, "Tons of love to wrap around you," and instructions to return the quilt when it was no longer needed so it could be cleaned and rededicated to another Sister in need of comfort. "It brought me to my knees," Elston tells the group. Later, after dark, the campsite has transformed into an otherworldly festival of lights, with a blazing campfire in a round concrete livestock feeder, a gazillion stars against a black, moonless sky and, in front of the Cowgirls in Paradise trailer, an 8-foot palm tree aglow in green and white lights. Dean Martin croons from the boom box as the Sisters huddle close to the fire and each other in the chilly night air, raise wineglasses and coffee mugs in a toast to the night before retiring to their warm, illuminated, impeccably appointed bedrooms on wheels to get some shut-eye before a planned fishing excursion in the morning.