While there aren't any strictly Greek places in the area, there are some options for good Greek dishes. The rule of thumb is to look for other Mediterranean cuisines, who might borrow from the Greeks.
The best gyros, bar-none are at
Café Mediterano. They're carved from the big rotating kebab (the only one I've seen in Vermont) and get about 10% more awesome every time I try one. Last time, they tasted just like at my old standard back in New York.
There are Greek desserts and a kick-ass souvlaki at
Betty's Beef and Seafood in St. Albans. I haven't been yet, but the owners of
Papa Nick's in Hinesburg are Greek and do a Greek night every Thursday. If you're in Johnson,
Farah's has the best dolmas I've ever had. Her spanakopita looks great, too.