Very cool you have some space to do this! I Haven't yet built a mock up service station, but I would like to someday. I'm driving across country right now, and whenever I see a cool old station I take a pic. One day if like to replicate one of these stations, maybe at least. Anyway, I'd check out the old photos from the net and see if anything catches your eye. So far I like an old station in Calumet, MI the best, it has a curved entry and some interesting brick work, ironically I don't think there's an island. If I was building something like your describing I'd make it God awful impossible for people to steal, rash of thefts in rural areas has been scary. Sorry not much help.
