T does not go to Wellsley. But here are some options:
1) take cab to Riverside Green Line station ($10). Head inbound ($2). Get off at Gov't Center and follow a) or b).
a) Leave station make right on Cambridge Street then a right onto Staniford. Staniford merges into Causeway. About 1 mi walk. Roughly 1:20 minuets.
b) Change inbound trains. Take Green Line to North Station or Lechmere. Get off at North Station and walk across street. Roughly 1:10 minuets.
T runs consistently until 1245.
2) Take commuter rail from Wellsley Hills (Worcester Line) to South Station ($6.25). Get off train and get on subway ($2). Take Redline towards Alewife. Get off at Downtown Crossing and change to Orange Line. Take it towards Oak Grove. Get off at North Station. Walk across street. Roughly 50 minuets.
T runs consistently until 1245. Commuter Rail is a varied schedule. Check here for schedule:
http://www.mbta.com/schedules_and_maps/rail/ 3) Take cab to Waltham ($12) or Brandies (may be closer to where you are). Take Fitchburg Commuter Rail inbound ($4.75). Get off at North Station. Take escalator to Garden. Roughly 40 minuets.
4) Take a cab direct ($45 each way). About 35 minuets.
#1 is the most convenient public transit option b/c you are not on a schedule to hit the train going in or out. So if you are late getting in or want to stay after and grab some beers you don't have to worry about missing the train. But it is the longest ride.
#2 is probably the easiest in terms of getting you back and forth to Wellsley Hills. But it can take upwards of an hour if you can't hit the subway cross overs. That can kill you if you are trying to make the last train back out of S. Station.
#3 is what I would recommend b/c it takes you directly to N. Station and is the quickest. Again your schedule is pretty tight as far as having to make the train.
#4 is the easiest but cabs are expensive. I took a cab from Fenway to Waltham last summer and it cost me $35 one way and Fenway is much closer to Waltham than N. Station.
Personally I'd take the 4:45 pm Fitchburg train into N. Station. Walk a block away from the city, cross the intersection and make a right onto Washington street. Follow this down past the park and make a left onto Salem and go to Ernesto's for pizza. Walk back up to the Garden get in. Watch the game. Head down Portland St hit one of the bars for a couple beers. Follow Portland to the end and go into Haymarket Station. Take the Greenline to Gov't Center change for the Riverside train go to Riverside and get a taxi.
Call these folks for taxi options they are the best!
http://www.veteranstaxi.com/