Worst case scenario

Got the valve cover off and started measuring clearances: Some of them definitely need to be adjusted since they are on the tight side. This means the cams come off, and I have to check the numbers on each one of 16 tiny little shims under the valve lifters, get the right thickness replacement shims, and put it all back together without messing up the valve timing. Not completely unexpected, but definitely something I wanted to avoid.

Took some time cleaning up the valve cover, particularly the gasket area, which had some old silicone and gasket adhesive. Non-chlorinated brake cleaner seems to do a good job of this. Tried polishing up the valve cover with some old Mother's Aluminum and Mag Polish. I say "old" because I've had it several years and it was a little crunchy on top, but I did make some progress. Then I spilled it all over the place. Finished cleaning the cover with brake cleaner, WD-40, and carburetor cleaner. It's not super-shiny, but it'll do. I slipped the cover back on to keep bugs out of the cylinder head.