Sourced a NICE clean tank $50 out of a 2001 manual Trooper (yes I took the AR5 too!) in Albuquerque, NM
Got it home, and I don't know how i overlooked it, but God how I hate U-Pull-It yards....

Drain plug in the middle, still in place, and punched holes on either side. SERIOUSLY GUYS?????? You can't take the 20 seconds to just pull the drain plug???
Sigh. Well, its all scrubbed out (lacquer thinner and then acetone) and airing out in the dry New Mexico air. We'll weld up the holes, and mount it up later this summer.

And no, I'm not worried about blowing up (not that I haven't considered it, but I think we have taken very reasonable precautions). I cleaned the tank out. Its air drying - for 4 months in New Mexico which has to be about as dry as dry gets. I'm certain there will be NOTHING to smell left in the tank, much less be at risk for combustion. And I am FIRMLY of the conviction that there is no WAY enough gasoline could "permeate the metal and outgas" to be any kind of a fire risk much less an explosion risk. (But thank you all for being worried for me!) And I will try to remember to get photos!