[Foiled Again]

There is a sort of triangular foam insert available at Bed Bath and Beyond called "instant king" - which is supposed to turn two twins into a king mattress. I don't know if this would work, but it might be worth it.

I too vote for the foam topper, especially if you carry a small vacuum onboard. Most people don't realize that a plain large garbage bag will work just like a space bag if you vacuum out the air. That would compress the foam topper for storage.

Another option would be an Aerobed (or a coleman air mattress which is similar but much less expensive). Try an air mattress, which can be deflated and stored easily.

Paula