Hi Ken,
My first BMW was a used/pre-owned 1989 325i cabriolet (alpine white, blue top and full blue leather...gorgeous!!)
I purchased it from the original owner, who had almost all maintenance work & repairs done at an authorised BMW dealer (Sterling BMW, Newport Beach, CA).
I owned the car for a little over a year, and had almost $3000.00 worth of repairs. It is my personal experience, my aunts older 3 Series and at least 2-3 friends with older E30s, is that while they are fun cars, and can be somewhat reliable....the maintenance is very frequent, and very expensive.
50 miles is quite a distance to be away from a repair center, and if you're not so good with home repairs and diagnosing problems....I would not consider a 1988 BMW. I honestly do not think that BMW became "reliable" until the late 1990's. I know there are going to be a lot of people who disagree with me, but until the 1990's, Mercedes was the most reliable German car on the road. Until the early 2000's, 99% of all taxis in Germany were Mercedes (due to their amazing reliability), not BMW. Now I think BMW is much better than MBZ, but a 1988 BMW is going to be a big headache. Sorry!