It depends which direction you want to go. If you are visiting Tufts, there is a hotel in Porter Square which also off of the Redline (T). If you have a rental car, I recently stayed at the AC North Boston and it is technically in Somerville. It is easy to get around Metro Boston from this hotel. The North End is 10-15 min by car, yes Davia Square is 10-15 min also. Otherwise, I would look to Cambridge area (Harvard). If you are going to use public transport, i.e. Subway, then look for stops on the Redline, Porter Square, Harvard Square, Central (toward MIT). Hopefully , this will give you the hang of it. Could always try airbnb.
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