I found a thin leather blotter and cut out the center so I could still get the machine out of the cabinet but cover the damaged veneer on the top of the cabinet. Now you can't tell it's damaged.
I took apart everthing on the outside of the machine, cleaned/de-rusted/de-tarnished/oiled anything that needed it, and put it back together again. Replaced the tensioner bits. Got a new belt on her. Practiced a little bit and discovered how easy it is to use a treadle machine, and she sews like a dream! Every time I go to sit down at my computerized machine I find myself wondering if what I'm doing could be done on Tiffany.
Found a shank adaptor and now I can use my modern snap-on feet her as well. Yay!
My only problem is getting the bobbin thread to run correctly through the shuttle. It takes several tries to get the thread in there correctly so the thread easily pulls out. Sometimes the bobbin gets stuck and won't move at all. I'm thinking of getting a new shuttle to see if that helps.