With some pointers (Thanks, AuroraLee) I've found information on clusters of surviving drive-in theaters in Nova Scotia and Ontario provinces, but essentially nothing for the rest of Canada.
Scouting reports and pictures are beginning to come in, the first from Fort Collins, Colorado. This is fun!
I've opened up an expense log for the project and made the first entries. First a subscription to updates for my GPS maps. This isn't just for the latest maps: many DI theaters are featured in the Points of Interest feature. Key in a city, hit POI, then Theaters, and often you get an exact location and travel time directly to the theater. Also got a sub-program for the GPS that lets you find the cheapest gas near your location. I figure that ought to help stretch your backing dollars into a few more miles. Gas directly at Interstate exits is always overpriced. You can save a lot by just going a couple of miles from the highway, but which way to head in an unknown locale? $19.99 ought to come back pretty quickly from that purchase.