I didnt carefully read all previous posts, but it did remind me of something called the "mattress genie"

http://sitincomfort.com/mageinunbedl.html perhaps you could invest in one. it is supposed to fold neatly for travel, and you can slip it under any mattress. if you get two, one can go under knees, and one behind the head.

I too dont sleep well away from home. I find alot of mattress' too hard! folks buy into this "hard is good for your back" bs, and then its like sleeping on a rock! I want a soft, comfy bed. I want plush, deep, and cushy. I dont want to lay on a slab.