Philly to Charlottesville
As you can see, you have two major options. If you're thinking of coming down I-295 from the Philly area, headed towards Wilmington DE and points south, your first headache will come on the DE side of the Del Mem Bridge - with all the construction there, the southbound lanes of I-295 that feed into I-95 are ALWAYS backed up on Saturday mornings. Trust me. We were just through there on 7/16. So I'd stay in Pennsylvania, and take I-95 thru Wilmington, or I-495 down along the river, and thusly stay west of the crap at the Del Mem. But we don't know exactly where you're beginning from, so it's hard to say.
Once you get past the spot where all three roads join up, around Christiana, it's not so bad. Four or five lanes southbound, even more when you get near Baltimore. If you decide to stay on I-95, the only concern you have is the prohibition against Propane in the harbor tunnels. You need to take the I-695 bypass and the bridge, rather than either of the I-95 tunnels - IF you have those big ol' tanks off the front end of your towable. If you don't have those 20+ pounders, I'd just slide on through the tunnels. Then stay on I-95 and the eastern I-495 beltway past DC, following the signs for Alexandria.
The somewhat less 'hectic' alternative is, as mentioned, US 301/50 (mostly 301) Follow the directions above taking the DE 896 exit off I-95 (I think it's 1A) and sliding south to hook up with US 301 a few miles down the road around Glasgow. 301 down through the Delmarva is a nice, flat, relaxed ride with only about three traffic lights between Wilmington and Annapolis.
Well, actually, there are a couple more, but not until you get to the bridge across the bay, where you've hooked up with US 50. About a couple of miles on the other side of Annapolis, 301 splits off to the south (take it) and 50 heads directly into DC (don't take it, unless you're planning on lunching on the White House lawn...)
It's not too bad, but as mentioned, there is a stretch around Waldorf/La Plata that has some traffic, but it's really not bad. Once past La Plata, and over the Potomac River, it's smooth sailing through Fort A P Hill and then you will see all sorts of signage hooking you back up with I-95 just north of Richmond. You're going to look for the I-295 WEST or NORTH leg, since you're heading out I-64 to C-ville.
If it was me, I'd do the US 301 route, especially if you've never done it that way. It's really night and day from I-95. Apart from Waldorf area, it's a smooth, easy, ride.
Here are some sample shots of what the 301 route looks like, taken at various times and dates in the last few years. (They were taken going NORTH, but you get the idea..)
Always remember, you're a unique individual - just like the other 7 billion people on the planet...