We live in NH and wanted to avoid going I95 through DC, etc.
We went in April and took the following routes
caught I84 in CT then I81 in PA through Harrisburg, PA
this took us through the rest of PA, Maryland (approx. 20 min) and W. Virginia (approx. 30 min) into Virigina
From there we caught I66 to Rt 17 which took us into Fredericksburg, VA where we caught I95.
We left on a Friday at noon, drove until 11:30 pm and stopped at a
Walmart in Hagerstown, PA (along with at least 30 other RV's). We slept approx. 2-2.5 hours (excitement woke me up). We left at 1:30am and arrived at Ft. Wilderness at midnight Saturday night.
On a side note. We stopped at the same Walmart on the way home. It's quieter than the truck stops and both times the lot was full of RV's (MH, travel trailers, 5th wheels). It's next to the interstate so you'll hear the cars but it's not that bad. The bonus is that it's free.
It took us 36 hours total only because we hit heavy winds in S. Carolina. We stopped at a rest area to have an afternoon nap, take a shower, have lunch and wait for the winds to die down.
On the return trip we did hit some traffic in the area mentioned above but it only delayed us 30 minutes or so. It took us 32 hours to get home.
We drive 55-60 so it takes us longer but we feel safer doing so plus it saves gas (MH gets 8MPG). We stop every 300-350 miles to refuel. Not that we have to but DD3 needs to get out of the car seat to stretch her little legs.
I monitor the open roads forum (RV people) and asked several people what the best route would be. These are people who drive to Florida several times a year.
Most say the route above is the best although many say to stay on I81 then I77, I26 to I95 in S. Carolina. They say it's a beautiful route and there's less traffic. The problem I've read with taking this route is that it's got some mountains (steep grades) so winter travel can be tricky. It's also approx. 100 miles longer. When you drive from NH the least amount of traffic and straightest shot is the route I vote for!!!
I'd say either route is good but if your traveling in the winter (as we will be on our next trip) that I81, I66, RT17 to I95 is the way to go.
We found that night driving was better as there were less cars. There are lot's of truckers and some of them made me nervous but I figured they do it all the time and at least they don't cut you off like the cars do.