One of the moderators on one of the Grand Design forums lost his fifth wheel to a truck fire while on the road (the fire spread from the truck so quickly there was no way to get the fifth wheel unhitched). They used the fiver to travel all over the country for extended periods of time. A number of us were surprised when he replaced the fifth wheel with a travel trailer with a similar floor plan. His goals were: 1) keep the living area on one level as they get older, 2) put a shell on the truck for storage space in the back, and 3) have room for a small boat on a rack on top of the truck. As an engineer, he implemented all of these goals rather elegantly. They still make trips all over the west (they live in Arizona) and pull up to rallies in Indiana. They don't stay gone quite as long as they used to (a month or six weeks compared to the three months at a time with the fifth wheel). They seem very happy with the whole setup.
Rob