1)Good public transit - 4 metro stops (Shady Grove, Rockville, Twinbrook, White Flint) plus the Metro Bus system, Montgomery County exclusive bus system, and Barwood (Mont. Co.) taxis that wait at metro stops. Metro stops running around midnight on weekdays.
2)If you are renting, try an upscale condo community like King Farm in North Rockville or something around White Flint (closer to shopping). If you are buying, go for Manor Country Club ($1M+), historic Rockville ($750K+), or Croydon Park ($400K+). There's really not much around for less than $400K and even these are older, smaller homes.
3)Try
www.rockvillemd.gov for city and probably county services, as Rockville is the county seat.
4)If you want a nice rental unit, don't plan on having a car, and are looking to have a decent social life, you should be in the $45K and up range. If you're looking to own a place and have a car, you'll probably need to be at least at $80K, and that's a stretch.
5)Community events (I used to live in King Farm - they do BBQs, wine tastings, etc), or join a gym and actually sign up for the aerobics/sports classes they offer in addition to the base membership.
6)If you have a driver's license, bring everything - UHaul/Budget trucks are affordable and you can return them to the nearest location after your move. I'm sure you can hire moving help both in New England and locally.
7)Rockville is a very nice place to live. One of my favorites in the immediate DC metro area. Good luck!