Those old stations are great. Try to put some time into studying old pics on the web to get all the exterior trim details correct, like soffits, roof overhangs, and mouldings. A little thought and a very small extra amount of money can make it a real knockout.
The only thing I am concerned about is your choice of 8' wide doors. I guess it depends on the width of your cars, but I prefer a 9' minimum....but I know that might throw off the proportions of your style. I like 30's-40's style stations, and I'd be at a loss as to picking a garage door style.
I think your project is great...I hope you keep posting..