I live in RI and only go to Boston on the train. Get a taxi from Logan. Do not rent a car- repeat do not rent a car. Parking rates at the hotels run about $40-$50 per day. That's more than you will spend on taxis and the T. Copley square is a great place to go shopping. Also Newberry St. Tons of great places to eat. Take a duck tour if you have time. Or walk the liberty trail.
It's a great place- just not to drive in. I ended up in places the cops don't want to be. And driving to the airport to pick up our daughter, we were looking for the parking garage, missed it and ended up on our way to NH. TWICE!!! Have fun.
Cheryl