Well after struggling with the key in the gas cap, I took it to a locksmith.
He was able to pick the lock, and we got the cap open. He unscrewed
the screws holding the cap on and said he'd have his brother(who
"had better eyes") make me a key.
Here's what the fuel gauge sending unit looks like. Note the solidified gasoline.
In the meantime I took the tank back home. Now that I can see inside,
man, what a rusty mess! So now, how should I decide if the tank is
salvageable(worth spending the money for a Kreem kit?)
In the mean time, we've removed spark plugs - can't say that they look
bad, but we'll replace them anyway(too cheap/too simple not to do it
while we're here).
We also tried an experiment - we had the bike on the centerstand, put it
in 4th gear, and then tried to turn the backwheel, in order to see if
the engine turns over. I'm no he-man, but I expected to be able to turn
the wheel. Nope. Does this mean the engine is locked up?