Well, it's kinda long.......... please bear with me !!!!!
Coming North on I95 into the DC/Baltimore area you have 2 choices to avoid I95 Parking Lot.
Option #1 - Get off I95 BEFORE getting into the jungle. Get close to DC and get on the I495 going North for about 10 miles, screaming, cussing, cringing, and frowning all the way. Exit the I495 at the I66 interchange and head West heading toward Strasburg. At Strasburg, pickup I81N toward Harrisburg. At Harrisburg, I81 and I78 run together for a bit.
Option #2 - Getting off of I95 on the North side of Baltimore. This is after you have used I95 through the DC Beltway Parking Lot and have really gotten yourself upset, your wife is screaming at you, and the kids are all pulling their shirts over their heads so that they won't see all the Doom's Day Events. If you elect this option, use I695 around Baltimore, and on the Northern side of Baltimore, exit at the I83 interchange and head toward Harrisburg. CAUTION, don't get on I76 in/around Harrisburg, it's TOLL. I83 will interchange with I78, your desired route.
Of these 2 Options, I recommend #1.........
OK, your on I78 heading North to Nova Scotia (eh) !!!!! Your on I78 heading toward Easton until you get to US33 (4 lane, toll free) near Easton. Take US33 North toward Stroudsburg and the I80 interchange. Get on I80 heading East toward Morristown (traffic can get heavy and insane, recommend NON rush / week end travel).
At Morristown, get on the I287 (US202) and head North toward the New York State line. After crossing the state line, you'll want to get on the NYS Thruway (I87) at Sufferin (TOLL) and head North, using the thruway for about 15 miles.
Exit the thruway near Newburgh, picking up I84. Heading toward Hartford, keep following I84 until it end, running into the Mass Pike.. Go East on the Mass Pike (TOLL) for about 15 miles and exit at the I290 interchange. Take I290 until it merges with the I495 near Marlbrough. Stop here for 2 cups of coffee, a handful of aspirin, and 3 slugs of anti-anxiety drugs............. Get on the dreaded I495 heading North for about 50 miles. It's reasonably smooth, lotza traffic, and I recommend NON rush hour travel. Week end travel can be real spotty, varying between bumper-to-bumper and wide open spaces. Friday PM and Sunday PM are guaranteed headaches !!!!!
Get back on I95 near Newburyport. Stop at the Bean Outlet, let the wife go shopping. Stay in the RV and chug a 6 pac of Molson's for having survived the I495!