You will find the highest concentration of 'snowbirds' and 2nd home owners in the lakes area, by far. If you are looking into being not more than 1 hour from Boston (and this depends GREATLY on what time you are venturing into Boston!) you'll need to be in southern NH, preferably the south side of Route 101, and not much further west than Nashua. It's not an accident that his is the highest concentration population in NH, for the very reason that you mention.
Other than being an hour from Boston, what other sorts of things are important to you? Need in-town grocery shopping? Lots of towns, even in southern NH, don't have a grocery store (and the residents like it that way). Need public water and public sewer? Natural gas a preference? Want malls, restaurants and theaters nearby? We'll need some more info about what's important to YOU to give good advice