Tim,
Cool site,  The Bel-Air was also the main one we when to as kids,  I still got some super 8 film of it from I think from 1980, I like the way the letter had that waterfall effect, also you're  right about the Ford-Wyoming , would hate to get car-jacked in a drive-in! 
TomFromJersey, 
 I was in the same boat,  the US-23 drive in Flint. MI ride home is  over a 1 1/2 hour and when the last movie ends @ 1:30am you don't want that long drive, so last year we stayed at the KOA that was 5 minutes away.  Worked out good. lately we been going to the Ponitace Silver Dome drive-in, only 20 mins ride home.
I checked  out the CFTBL pinball 
http://www.ipdb.org/showpic.pl?id=588&picno=8536, I remember it,  still a hot one for collectors. Pinball is another thing I like to collect more of  only got one now. 
The Gratiot drive-in was the one with the waterfalls, but by the time I when in the earlier 80's,  I don't think they were working anymore . 
Also does anyone remember the Northtown theater ?  it was a inside thearter located on 7mi & Van Dyke in Detroit, I remember see Batman there in 1966 when I was 4. It was very Art Deco inside because it was built in 1936 
http://www.waterwinterwonderland.com/location.asp?ID=703&type=5Ray