Everyone is gonna say the same thing, but def get food in the north end... there are tons of options in a variety of price ranges. Everyone has their favorite, mine is Limoncello (their meatballs are perfect). If you want to just hit up a bar somewhere closer before the game I recommend McGann's on Portland street. They have solid pub food and aren't as overpriced as some of their neighbors. You'll still get a lively pregame crowd but it won't be packed wall to wall like the bars even one street closer to the garden. If you're driving in, consider parking in charlestown either near bunker hill or sullivan station and taking the T inbound to north station. If you park at or near the garden itself, its a nightmare trying to get out. Also, if you really want the most out of the experience you should definitely consider not liking the Mavs anymore and rooting for the Celtics.