I just have a one-person, 40 lb., 10.5 ft. kayak, but I put it on top of my a-frame with a simple cartop kit from Fleet Farm (maybe $19.95). I used the foam blocks that came with the kit and added some of those long foam swim noodles for protection on the camper. The noodles also work great for getting the kayak on and off the top of the camper by myself without damaging anything. Strapped it down with the ropes provided by the kit - front & back, and added a ratcheting tie-down across the middle, side-to-side over the top of the yak and under the camper.
Cyndi, Stu the Wonder Dog & Mandi the 10# Guard Dog!
2012 6 cyl. Toyota Tacoma Double Cab
2013 Flagstaff T12RB A-frame