The amazing Peter Flanders of Ocean Breeze RV returned later this week to help with the stubborn toilet flange I haven't been able to budge. With a large pipe wrench and the right amount of leverage, it finally dislodged. It was indeed threaded and the amount of effort it took suggests it was possibly set with a compound. Now I'll be able to install a proper flange over a new sub floor without a make-shift adapter.
With the warm weather here (finally!) I've been itching to get the camper out. It's too wet around the shed to tow and it won't be dry enough for at least a few more weeks. To get things going I tacked a couple of wheel stops onto the ramp and got it just far enough out the door to lift the roof. Walls are now completely routed and ready for the next ceiling panel. Bathroom build to begin next week. I also scored some sibling labor and the countertop is almost completely sanded.