It was made for horses. The area around North Station is the absolute worst for cars, it's chaos. I agree those are the only real option aside from parking near a T station somewhere. I don't know where
@Dibbie is coming from, but there are quite a lot of surface lots near Kenmore square/Fenway. Could take the Green Line to the Garden. I'm sure the train will be crowded after the game but probably less so than for a Cs or Bs game. Driving a truck in the vicinity of North Station is daunting enough, even if you don't park it. If coming from North or South that may not work.
For people coming from CT, it might be viable to stop in Framingham (or another station), take commuter rail to Back Bay station (it doesn't always stop there) and then the Orange line to the Garden/North Station. The commuter rail lots are big surface lots and will be mostly empty on a Saturday.
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