Flying in MD

Looks like I'm moving from MN to MD. I'll probably be living in or
very near Germantown, so I have a choice of three airports I can use
to finish my instrument rating: Gaithersburg, Davis, and Frederick
(GAI, W50, FDK) in order of increasing distance.

Other than trading the relatively free skies over the midwest for lots
of traffic and big fat ADIZ, what can I expect? Any mountains nearby
I can get experience with? How's the weather in the winter? Anything
to say about the three airports and their flight training services?

I can look all of this up but it's funner asking you.

-Scott