JJohnston, welcome aboard. Do check out the info available here regarding trailers that are high enough to stand in. I do believe that a rig for 2 adults and 3 kids, would be a tight squeeze for a 4 x 8 trailer. However, stranger things have happened. Check out some of the "slide-in" units that some have built. Good luck, get started soon, take pics, post em, ask questions, and get involved with this bunch of happy campers.

Roly