So this panel took far longer than I'd hoped, and I ran out of adhesive, so that's as far as I got day before yesterday on tub surrounding. My son asked with some apprehension whether the masking tape was permanent. I assured him it just holds the panel on the wall while the glue is setting, and he was greatly relieved.
Note the strip of ugly old adhesive along the right edge. Fortunately, that stuff scrapes off pretty easily.
Anyway, yesterday we shopped a lot for various things required for a household, as opposed to a house, and so no more progress was made on that front. I did start installing the front windows (hoping to get a little breeze into the south side) but it turns out I'm going to have to plane the sill down a little; it's warped slightly, just enough that I can't get the pocket replacement in on the right window. Ah, well. Onwards.