Damage and rot = window seals (butyl tape, have to remove the
windows to do it), wood around
windows and belly band. Those along with the body to frame bolts would be the first thing I do to a
Trillium. Lots of threads on
Trillium door hinges and various levels of repairs to the wood that the hinges bolt into.
Floor rot is bad problem to have on a
Trillium due to the somewhat unique interior construction. Preventing water from reaching the plywood sandwiched in the floor is job 1. Fortunately the design of the Trillium makes it less likely for water to reach the plywood. But if it does, I am still waiting to see someone tackle that job. Rot in the flooring on the rear dinette is something others have tackled. Its the main floor from the kitchen to door. Look for sag across the floor and the roof, as well as soft spots.
I looked at two Trilliums before I bought mine (#3). The first two both had serious main floor rot. Both of them
sold to others. Kind of waiting for those buyers to appear on this forum.
David Tilston and Randy Bishop are two forum members that have owned many Trilliums and have done extensive rebuilding. There are others too with ample experience, which has been a huge benefit to me!