<p>Jamaica Plain is not convenient to Cambridge. The distance is not great, but taking public transportation would require 2 subway lines. There may be a bus, but I’m not sure. mbta.com has a trip planner.</p>
<p>The commuter trains from Waltham go into Boston (North Station; VERY inconvenient), not Cambridge. There are no commuter rail stations in Cambridge, only the subway and busses.</p>
<p>I agree with other posters that you don’t try to drive/park in Cambridge. I would stick to the Red Line.</p>
<p>Fendrock is correct. Some commuter train lines stop in Porter Square. It’s about 15 minutes to downtown Waltham and 17 minutes to Roberts station at the foot of Brandeis. I think the fare is $3+ one way. The T fare is $1.75 one way, so a round-trip would be about $10. Cheaper than trying to find a parking space (especially since in many places, you have to move your car, you can’t keep on feeding the meter).</p>