>>Did this by using a selection of data to translate coordinates into addresses. I had to map distance as-the-crow-flies from the dealership to its max distance radius. Then calculate and find all coordinates that were within distance X from the dealership.

Very similar to this, which I don't want to re-do:
http://www.sqljunkies.com/Tutorial/21DC68CD-1A97-4909-8157-523CA249CC80.scuk
Its a good demo of what I want to do.