This hardly counts as a mod, but it worked well for me. My trailer fetching trip was made with a friend. We both tend to be the modest type and the Trill is not exactly built for privacy. How to delicately handle porta-pottie usage and clothing changes without requiring someone to wait outside?
It dawned on me that a simple shower curtain tension rod could be placed across the trailer between the closet and the kitchen cabinets. I threaded a spare sheet over it and voila, privacy with little trouble and very little weight
. Easy up, easy stow, and cheap. It allows just enough room to slide the pottie back and forth as needed at night (gotta stop drinking so much water!) and enough room for both of us to change in complete privacy.