We are about a year into a similar venture in NW Arkansas (Bentonville). My husband and I moved here from Seattle about a year ago, and opened two drive-thrus. After almost nine months, the first one seems to have passed a hurdle and is consistently doing well. Our second location is only two months old, and it is the same battle all over again to build up a customer base.
Lots of nay-sayers told us that people in Arkansas wouldn't go for gourmet coffee and espresso, but we've been pleasantly surprised by the uptake here. We're near Wal-Mart corporate HQ, so there are tons of transplants from big cities. We knew they'd be thrilled to see a drive-thru espresso (we were the first), and they were. There were also plenty of locals who had seen drive-thru espresso in other parts of the country, and were glad to finally have one in their own backyard.
My advice to you is to do your homework. Get traffic numbers from the city and make sure your location could survive by pulling 1% of that traffic in every day. Also, research the surrounding demographics. Are there lots of office parks/schools/affluent neighborhoods near your store? If it's all blue collar/low income, you may want to reconsider.
There will be PLENTY of people telling you that your business/location stinks. If you're confident in the choice you've made, then go for it. However, even with everything going your way, be prepared for a lot of hard work! You will literally be building your business one customer at a time. Starbucks just opened up their first stand-alone store here, and I agree with what another post said regarding "the big green monster." Starbucks should help you by doing the heavy lifting in terms of customer education and gourmet coffee awareness.
I could ramble forever about what I've learned in the past year, but I hope these few thoughts are helpful.
Best of luck to you!!