That weekend is super, super busy in Boston because of the Head of the Charles Regatta. I would lock in a car now.

When you say "visiting Boston" you really do not want a car for your time downtown. But if you are landing at Logan and heading out of town that's fine.

I'll be there the same week. No car when downtown, then Saturday 10/22 renting a car at Avis on Atlantic Ave. and dropping at Logan 3 days later, $101 including taxes. It was the best I could find, and saves me getting to Logan for the pickup. This was through Costco.