I also added a Thetford 565P to my Northstar TC800. I adapted the cabinet at the camper rear next to the dinette and outside door. To keep it simple, the toilet will slide out into th aisle for use. My wife occasionally sleeps on the dinette bed.
Original picture minus door.
All ripped out. Glue and staples are hard to remove.
New door made with mdx and veneer, and stained to match.