No way would I invest in a carbon bike at 355 lbs. I would go for the least expensive, best fitting bike regardless of frame material.
I would have to second a stock crosscheck. They really are nice bikes, and for what you want, I think it could serve you well. Not to mention most local bike shops can get them, even if they dont stock them. Build the frame up with inexpensive components and decent wheels.
when I built mine, I think I had about 1500 in it several years ago and I used an apex group I found off ebay.