maybe rent a bike or two from a shop.
The Trek FX line aint bad, it's what i ride right now, and has been reliable for the short time ive had it. Sans one flat.
There are better bikes beside Trek of course, some cheaper of coruse and some more. I say just go rent some and see whats up, 290 lb/s isnt exactly light, sorry lol! It's ok man i was up to 230 3 years ago, and started karate and lost 50 pounds..im about 185 right now...the cycling helps, but dont burn the weight a good shotokan class will burn.