Take a look at I-90, I-79, US 19, I-77, I-26 then pick up the I-95 south east of Columbia, SC. It seems to be the straightest route, US 19 is a four lane with traffic lights at places, but a good road. There are some hills in WVa to deal with.
We use the reverse route going to our son's place in Hamilton before beating it down to the Maritimes for the summer on our way home from Fla.
There is a year round campground about 40 miles north of Pittsburg on the I-79.
After that there are more campgrounds as you go south so lots of options for overnight stops.
Penn, WVa, and Va DOT all have highways camera sites so you can keep on top of the weather along the route.
PM me if you need more.