Being as it is so early, your Trillium
may be different than later ones. But typically, the original "furniture" is fiberglassed in, as far as I know. This is actually a good thing as it eliminates any hull penetrations in that area (such as for rivets). Not that there's anything wrong with rivets, but furniture tabbed in with fiberglass is even more maintenance-free. However that means its not easily removable.
Again, yours may be different because of being such an early model.
And, not to be a downer, but I can only imagine that the windows
leaked, and the PO felt that caulking around the outside was the way to fix it. Unfortunately, that's not true. What needs to happen is for the windows
to be taken out of the camper, the caulk cleaned up, and then the windows
reinstalled. In the case of the framed windows, this would be with new caulk or butyl tape. But not around the outside of the window -- it should go under the flange, between the flange and the trailer shell, and not on the outside at all.
I would say that the fixed window with the rubber seal should also be removed, cleaned up, and then reinstalled (or replaced) with a new seal and lock strip.
This sort of thing is regular once-every-decade-or-so maintenance, but people often feel they can get by with just globbing caulk on the outside (or they genuinely don't understand that's not the way).
Robin, I'm not sure who made the Add-a-Rooms, but they were options that came along with the Trillium
. I looked at one Trillium
that had an entire
"flower power" Add-a-Room (carlyi's has one "flower power" panel, it looks like).