Bought a tube of that lock graphite and put a little bit in the tank gas cap, and in the lock under the stove knob. Also took a little bit of Liquid Wrench (I forget which flavor) and spritzed it in the latch while depressing the tabs.
Here's the rub - I can buy ethanol-free gas in my area, but it's only 87 octane. Not enough for the Connie. It's expensive, but not any more than the 93 octane with the garbage ethanol in it.
I'm now examining octane-boosters (Gumout, Rislone, Sta-bil, etc.) to see if there are any issues going in that direction....