what would be the best way to do a trip in boston going to the aquarium, fine arts and the museum of science?

in one day, in what order?

One nice thing about Boston is that it is a small city where most attractions are around the downtown area at walkable distance. If you are not stating within Boston itself, you can take the commuter train to North Station and walk 10m North West (accross the Charles River) to the Museum of Science. Then take the subway Green Line to exchange with the Blue Line to Aquarium station (just about 3 stations in all). A cab should charge about 12-15 bucks for that trip. If you decide to start your day at the aquarium, you can walk from North Station as well (go South) for about 15m. The advantage of doing this is to see a bit of the attractions around the Freedom Trail (Faneuill Hall, the Holocaust Memorial, the Old North Church, etc). Finally you can take the Green Line again (ask what Train will take you to the Fine Arts Museum), or a cab (Around 15 bucks again). The FAM is near the Fenway area, I recommend going to Fenway Park and getting a feel for the History in this old park and the exitement for the Red Sox.

Good luck

That is a whole lot for one day. The MFA and MOS are HUGE and you could spend at least 6 hours in each one. I would start with the MFA which is the MFA stop on the E branch of the green line. You can take the green line back to park street and wait for a "LECHMERE" train which will take you to Science Park where you can walk a very short distance to the MOS. About a 30-40 minute trip. From there I would hop back on the green line to Haymarket and you can walk to the Aquarium from there or take the green line to Government center switch to the Blue line to Aquarium. About 20 minutes either way, a little more if you are walking though. It would be nice to end at the Aquarium since the North End is right there and you can get a yummy Italian dinner.