Ugh. Need to keep perspective!
It's become obvious that using the rotisserie will make the job a LOT easier. I know I'm not the first to wander down the path of "oh yeah, I can deal with laying on my back for hours, days, weeks and I'll just knock this out in no time" followed by "wth was I even thinking???". So I hauled out the rotisserie I picked up for a song a few years ago. But before I can use it, I need to address the rusted body mount point in the body I indicated earlier.
Started stripping the undercoat and whatever other black sealant someone had used during the last overhaul and found more rust than I would have liked. The area around the body mount seems pretty straight forward with the donor metal I have, although I need to do some practice welds and work up some confidence to do the job. It's been many years since I've tackled anything like this, and back then it wasn't on my own vehicles so it didn't matter as much (friends were paying me with beer because they had fewer tools and skillz than me!).
Anyhow, I get to the end outer end of the brace, where it meets the trunk floor and drop, and there's rust holes. I knew there had been some patches done to the trunk, but the work was pretty well blended in. Now I'm seeing that the replacement metal wasn't welded as there seems to be a lot of panel adhesive in there, and minimal to no rust treatment. Overall, things feel solid and the rotten steel isn't really in a structural location...but I don't know how deeply I want to dig into this! It might not be quite right, but for what I plan to do with the car and the number of years I have left to enjoy it, I don't think it'll matter if I avoid going all in here.
So, I think I'm going to treat the rust I can reach, cut an repair a bit of steel but not going to go full monte on any of this. I don't want to damage the visible paint areas of the car (paint is great as is, no reason to open another big can of worms there), but I don't mind having to patch/recoat areas in the trunk. It's going to be hidden by carpet anyhow and the rest of the work won't be seen by anyone unless they crawl under the car.
Anyhow, long story short (too late?), repairing the rear brace/body mounts in preparation for mounting the body on the rotisserie.