I can echo Ex-Ithacan's comments, he hit the nail on the head... As far as the commute, there are a few options:
1) Driving - expect an hour and a half each way, sometimes more, during rush hour. I have a similar commute (Crownsville, AA County) to Bethesda.
2) Metro - drive to the New Carrolton or Suitland station and Metro into DC, change lines, and ride to Rockville. Total time will again be about 1 1/2 hours each way, but you can sleep or read on the train if that is helpful to you.
3) Bus - there is a commuter bus route that you can catch in Deale or Owings that will take you to the Farragut North and Union Station Metro lines, both on the Red line that will take you right into Rockville. This might be slightly faster, but then you use 3 modes of transportation to get to work - not too effiicient
Good luck!