It's 78" wide, outside to outside. Yes the bed could go crosswise... but I opted to leave it lengthwise, so I don't have to crawl over Chell!
Do what I do, Lydia sleeps in the back, she crawls over me. It encourages her to use the Porta-pottie before we go to bed. Save 2' and some weight.
How about a big crank out window in the rear panel? Glaze it in Plexi. No weight penalty and safer than standard glass.
Jim