Clay my take: I would offer a 6 hour class that would make travel and a stay in a motel worthwhile. Limit the class size to 20 or whatever number you feel appropriate. Professionally video tape the class and edit for future sale.
$100 dollars for such a class would be too much a bargain so maybe $200.
Deciding what to cover in the class Test equipment, Early electronics - Bally/Stern/Williams/Gottlieb? WPC? Data East/Sega/Stern? EMs?