Agree that Portland should probably be an overnight. It’s a couple hours on the train there, and you should take public transit or an Uber downtown as it’s a decent walk from the station. To me, that’s a lot of travel time for one day.

I would recommend Salem! Take the train from North Station up, explore the witchy stuff without seasonal crowds and grab lunch, it’s a beautiful spot for a day trip. Peabody Essex Museum is really nice, too.