Tried again to remove the plate on the inside of the round cover on the left side of the engine, the black plastic piece that has those two springy magnet things. Ended up thoroughly stripping the heads on the two mounting bolts. So off I went to Home Depot, and picked up a set of easy out drill bits. Never used them before, and after about 30 minutes, I had both of the stripped bolts out. Transferred the innards over to the new powder-coated cover, used anti-seize on the bolts, and started the bike to make sure I didn't mess anything up. So at least now the left side powder-coated engine cases are on, so next are the oil filter cover and clutch cover (this will involve an oil change), and the three valve covers.
On an unrelated note, I noticed there was a small oil leak down by the right centerstand leg, and thought it might be coming from that cap on the breather tube that was hanging down around that area. I removed the spring clamp, twisted off the cap on the end of the tube, and all this oil just spurted out (maybe half of a small dixie cup). I let it all drip out, wiped up the mess, then put the cap and spring clamp back on. Since I have to remove the tank to swap out the valve covers, I might take a look at that breather hose, and see if there's something I can do (replace with clear vinyl to observe any output, reroute with a loop to keep any fluid from accumulating down at the cap, redo with a crankcase filter, etc).