Rosalind offers a nice private room in a quiet neighborhood. You won't miss anything for a short stay there and the area around is full of restaurants and access to a Walgreens. The house is only a 10 min walk away from the red line and 1 stop away from Harvard. A few more stops and you're in Boston Common, from there you have connections to every other line.
This is a much better location that most places in Somerville which are far from any T stops. It will save you a lot of money on Uber rides ($10 to pretty much anywhere in a shared Uber) if you get a 7-day ticket.