I drive from the FL Keys to NJ more times per year than I want to (just did it two weeks ago).
AVOID 95 from mid-VA to Philly! Especially with a 45 footer and a toad!
I turn off 95 in Fredericksburg, VA and take VA-17 to I66 W and then hop on I-81 which bypasses all the congestion. It takes about an extra hour but it is much more relaxing, avoids the inevitable accidents and ubiquitous construction, save you some tolls plus there's a great BBQ truck stop in Opal, VA.
Tom and Katharine
'07 Winnebago Tour 40TD, 400hp Cummins
'17 Winnebago View 24V, '02 R-Vision B+
RVing for 20 years & 200,000+ miles