Like K Charles said...come off the Cape onto rt 25 to I-495 say on 495 to the Mass tpke I-90 go west to I-84 in Sturbridge,Mass stay on I-84 to Newburgh,NY and go SOUTH on I-87 to Sufferin,NY and pick up I-287 to about 45 miles to I-78 to I-81 toward Harrisburg,Pa as you get close to Harrisburg ,you'll see I-83 to Hershey Park...
This is the way to go, especially if you are used to Seattle. Watch for Staties in CT, though. Just outside Harrisburg in Hamburg, PA is a large Cabelas. Great place to stop to do some shopping, they have a restaurant inside, and there are RV accessible gas stations across the street. There are also multiple truck stops on I78. Just beware of the semis that fly on that stretch-stay out of their way or keep up and there's no issue.
