1 word: Aerobed.
I had the world's smallest bedroom in college, so I used an aerobed to save space. slept on it every night for a year, and it only finally developed a leak a couple years later, after i'd graduated (and continued to use it while camping)
The $130 or whatever they cost is a lot for an air mattress, but the quality is worth it. They do require AC power, but they inflate in less than 60 seconds, so you probably wouldn't even need a generator, unless your pit neighbors are particularly stingy w/ their generator juice. The pump is totally integrated, so it doesn't lose air when you try to 'cap' the inflation opening. Really great design when I got mine in 2002(?), and I know they've only gotten better since then.
the biggest advantages I see w/ the aerobed are that it's light, compact, and portable. So you can use it for house guests, or in other non-trailer situations. It's honestly good enough that I wouldn't feel bad putting guests on it. Plenty firm, and you can add or remove air while you're laying on it.
