I got lucky. This mylar was like nothing I've handled before; it came off pretty easily without taking much paint with it. I used a hairdryer to warm up about 4 square inches at a time, and pulled gently. This is what it looked like coming up:
It was stretchy, like the stuff that you pull off of a new translite. And it was a dingy yellow color. But I was really happy to see this:
What looked like a cigarette burn on the playfield, was just orange dye that had bled from the clear orange inserts into the mylar.
I used Goo-Gone to remove the mylar glue at first, but lighter fluid works much better. You can see a bit of paint loss in the picture below, but it shouldn't be hard to match this blue.
I've only done the lower half of the playfield, but I'm pretty happy with what I accomplished in 4 hours. You can see that I've got some touch-up work ahead of me. But really, it's not that bad at all.
I really shouldn't have started this tonight, because I need to finish my 2009 taxes. I guess I'll do that tomorrow...