Feasible? Yes. Desirable? Probably not. The roads are generally terrible, as are traffic patterns. Your best bet might be to check out the Minuteman bike trail. If you can live somewhere near that and intend to use a beater bike or hybrid, then maybe. I’ve lived in Cambridge, Brighton, and Somerville, so feel free to PM me if you have any specific questions.
i work in the financial district and have bike commuted at various points in time from a couple of different locations. I have bike commuted from a town called Medway which is approximately 25-30MI southwest of the city. I did this three times a week and it took about 1.5hrs give or take. If it was too late to ride home I’d hop on the commuter rail with my bike and ride home from the train station which was about 5MI from my house. I have also bike commuted from Brookline, MA, which is about 5MI from the financial district and it took 15-20MIN and I have commuted from the Somerville/Medford area which is 8MI from downtown and took about 30MIN. Bike commuting to the financial district is possible but I suggest getting to know the “backroads” around the area as this will make for a much better experience. For the last year or so I haven’t been bike commuting as I was having too many close calls with taxis and the other crazy drivers downtown but definitely give it a try as it can be done.
There is a strong Tri presence around Boston and most of the surrounding areas offer pretty good riding and running. In my opinion (and I’m sure i’m missing some here) the suburbs with the closest proximity to Boston that offer good riding/running are Arlington, Concord, Belmont, Lexington, Wellesley and Newton to name a few. All are very expensive places to live but are often the focal point for numerous tri groups/training. If you go further out from the city you lose some of the structured training stuff but the locations offer great locations to ride/run such as to the North, i.e. Beverley, to the West/SouthWest such as Medfield, Dover, Franklin, Norfolk, Hopkington, Medway, etc and the south shore is also fantastic.
If you do end up near the city the one spot you will get familiar with is Walden Pond (off of Rt. 2). It is the meeting point during the season for rides/runs and swims. The pond is about 1/2MI across so it’s nice for swimming. The roads in the area offer some real good riding and the network of trails behind the parking lot requires three separate town maps to get a good feel for and you can run for 3-4hrs without hitting the same stretch of trail. Great spot!
I hope this helps somewhat, if you have any more questions please let me know if I can help. Welcome to Boston.
I echo the previous poster as well. Traffic is tough and roads are rough - you dont really want to bike much in the city. You’ll want to take public transportation to work and bike in the burbs. And exactly right about Waldon Pond - its where every tri club and AGer swims. Feel free to PM me with any questions on your move - best gym (Sports Club LA), best bikeshop (Wheelworks), etc.