Here in Palm Beach county, Comcast provides three out-of-market regional sports channels: CSN Boston, CSN DC and SNY. I would love to get MSG Network added, but since Comcast does not have a stake in that network (or NESN) chances are slim that they will be available anytime soon.
While some areas do have out-of-market regional sports networks, remember that all in-market broadcasts are blacked out. There is very little worthwhile programming available on these networks, as all pregame, postgame and other team-related material would be blacked out for the Red Sox and Bruins in South Florida.
I get METS pre- and post-game shows here in south Florida on SNY. Just the actual games are blacked out. I get those on my MLB.TV subscription. I believe that is also the case for Capitals games on CSN DC.