I think what you are asking is, do you get the games on mlb.tv if you are in the Sox "market"?
I don't know. I'm technically in, while being 2 hours away from, the Rays "market". The reason I don't know is because I've never attempted to watch the Rays on MLB.TV. I'd call their customer support and determine if you will be able to catch their games.
If, however, your question is if you will be able to watch Sox games outside the Sox "market", but inside another "market", then the answer is yes.
Hope that helps.
Also, when the Sox play a Saturday day game (1:00 pm or 4:00 pm start), and the game is not covered by Fox in your area, then you will be blacked out starting (I think) on May 17th, when Fox begins it's weekly coverage.