I have a new Coachmen Freedom Express 246RKS. While the toilet placement was fine, I wanted to upgrade from the cheap plastic Dometic toilet to a porcelin bowl from Thetford (had one in a motorhome and it is far superior). Don't know what toilet you have, but maybe another toilet would handle your problem. They all have the same mounting configuration. If that didn't work, the small magnets (circular, around quarter sized), mounted permanently to the seat and wall is a good idea. Another idea would be to mount one of the spring loaded catches that hold exterior compartment doors open. Then there would be nothing on the toilet lid to fall off or look bad.
CT51