Story: I just purchased an 84 300D which suffered stalling problems. You could drive 40-50 miles but then needed a tow home. Local shop replaced all kinds of stuff but didn't know the tank had a drain.

I had it towed from Philly and drained he tank. Messy, but not really difficult.
Make sure you get as much of the fuel out as you can before you start and buy one of the plastic mortar pans from Home Depot. $5. If you get the tank down to the point where the light comes on on the cluster you have about 3 gallons left.

My fuel came about fairly nasty, guage was fine and I never even cleaned the screen. The car has never stalled once for me. I wouldn't over think this. Start with the tank. Oh, you can inspect the tank in the car with a small flashlight. If you want me to contact me thru Stormwind Alpacas and the Google. dave