If there is an old school record store around, even if they don't carry 8-tracks, they likely know a collector. It's possible that a collector already has a setup to digitize their tapes.
I can think of someone here in Portland, Oregon. I'm hoping it's the same way in Boston.
Add: After reading some responses, felt this worth mentioning. It needs to be an 8-track stereo consumer machine. Not a cart machine from a broadcast facility. Same tape inside, but they ain't the same thing.