Central New Yorker here who loves making the 4.5 hour drive to Boston for a game. I'm 29, and think i've been to about 20. I am very fortunate!
Whenever I go I stay at the holiday inn Somerville. You do need to drive under the city through the big dig tunnels. I've never gotten stuck in any traffic going through there. The hotel is a 3 block walk from the T station and two stops away from TD Garden/North station. From hotel to the garden it's about 15 minutes on a bad day.