RE: I-81 vs I-78 in Pa.
The only time we use I/78 is in the winter and a storm is possible. We just came up 81 to 84 yesterday and decided PA has even worse roads tha SC. 84 is particularly bad but they are working on it and it's only about 50 miles. If you are staying at Tri-States make sure you use the menu in your packet and order delivery.... it's great!
RE: Route from MA to Myrtle Beach,SC with the least traffic
We always take the Pike to I/84 to PA. If the weather is good we stay on 84 to Scranton and take I/81 south. If it's threatening we take US 209 (first exit in PA) to I/80 to PA 33 to I/78 to I/81 just above Harrisburg. There are no mountains; so it's warmer and less of a chance of fog or snow. At Winchester VA you can take US 17 to I/95.
