I also second the idea of a reverse trip: PVD - Providence - Boston - etc...
Another idea may be Providence - Boston - Hartford - etc... Although a little longer, Boston to Hartford can be done on all interstates (I-90 to I-84) at 65+ MPH!

If you go Providence to Hartford, you'll be traveling on a 2 lane road for part of the way - Route 6. (They didn't nickname that section of Route 6 as "Suicide 6" for nothing!)
Besides, you may run into less traffic in Boston

at night.