I will accept free Chicago Schwinns most anytime!
Your "blind date" could have have been a lot worse and it's not a rust bucket. These Suburbans ride like dreamboats and yours will quite the lady when she is done - don't see many white ones, especially with decent paint. Your sweet Collegiate might get a bit jealous of the attention
For leopard skin tires, I take pliers and squeeze/crunch them inwards to break the sidewalls free. If they are real tight, cut the beads with wirecutters and strip them off with your pliers.
After I get the tire completely off, I shave off what tire gum residue I can with a single edge razor on the rim's top lip and lastly use a drill with wire brush on the innards.
If you let the rim get cold the old tire residue will be more brittle and easier to remove. Disregard that last part as you are in FL...
I would suggest using mechanical means first as once you use acetone or WD-40, etc to soften the residue, it will be gummy and harder to remove any remnants with the drill
Anyway, you should remove it
all from the inner sidewalls or it will be a PITA to seat the new tires. They are stubborn enough with clean rims...