Our son lived in Baltimore for a long time, and we got so we really liked staying OFF I95, which can be so trafficky.
So we often went from Baltimore north on I83 to I81 in Scranton, then I 84 just about all the way to the Hudson Valley.
You could easily take 84 all the way up to where it meets the Mass Pike, and then in to Boston.
It does avoid a lot of traffic, and it is pretty scenic going over the mountains in PA.

I would head up the Garden State parkway across the Tapanzee Bridge to 84 Eastbound to the Mass Pike. I would probably leave Baltimore around 9am as that would get you to Boston around 4-5. Or leave Baltimore around 4pm (get into Boston around midnight)

I have done that drive a few times and have thankfully avoided any issues.

We frequently travel from Baltimore to West Hartford, CT and have tried various routes. I agree that the Tappan Zee Bridge route to 684 and then 84 is the best. We've tried the Scranton route several times, and indeed it is a prettier drive. But, it does add on at least 1 hour to the drive, so it depends whether scenery or time is your priority. On the plus side, you can save a lot in tolls by taking the PA route. Also, if you hit a traffic jam in NJ, it can be bad. I'd suggest a GPS if you have one or look into some possible alternate NJ routes, perhaps 295 if the NJ turnpike is jammed up. Good luck!

Do find one of the NY radio stations that gives you traffic reports every 10 minutes or so if you decide to take the map quest route and if there are no tie ups it will be the fastest. That said, from the GW bridge if things look bad the cross bronx to the Hutchinson river pky which runs into the Merrit pky in CT then to 91 often is less tied up than 95 and as you near Hartford on 91, take route 3 east to route 2 west to 84 east and you will avoid going through the city. Also if you take the 684 to 84 route, a bit west of Hartford there is a 684 or 691 in CT which connects to 91 and you can then take 3 to 2 to 84 to avoid the city. In the Hartford area AM radio station 1080 gives traffic reports every 10 minutes during the heavy traffic times.