I live in VA and am very familiar with 81 and 95, in fact, I was on 81 yesterday evening. I am originally from CT and used to run up and down from the shore in VA. If you have the time, avoid NY and the Baltimore/DC area, period. Go SW from CT and use the Tappanzee bridge and down through PA till you can get to 81. 81 runs alongside the Blue Ridge so it's not mountainous; there are only a few short hills that are steep. The only problem with 81 is that it is a MAJOR truck route, so expect to run a little slower. IMHO, I would rather do 81 with the trucks than 95 with all of it's problems. We also have a sniper that's causing major havoc near 95 around DC; hopefully he will have been caught before Christmas.
You will need to cut south on 77 (I think; no map at hand) to take you down through the Carolinas as you move closer to 95, which you can pickup just before Charleston, SC. The whole trip is out of your way, but more relaxing and the scenery is much better. There are one or two grades from VA to NC that are long pulls as I recall. We've even used this route a couple of times in a car from Savannah, GA to Front Royal, VA, just to avoid 95.
I agree with Cliff about the weather. It's possible that a big storm dumping rain along the coast could be snow inland. I suppose it's a crapshoot. The mid-Atlantic states have had two very mild winters. Maybe you'll luck out this winter.
I have to agree with ralphie. I've done MA/FL several times and I really like the inland route. When you cut out all the big cities (NY, Baltimore, DC, etc), the 'longer' route might be shorter on time and is far more relaxing. One response mentioned the Garden State Parkway. Your MH likely doesn't fit nor is it allowed on the GSP. I also stay away from the Tapenzee. It is expensive (east bound) and the 684 highway from 84 to the Tapenzee is that concrete/seamed type roadway that shakes your bones.
So, I like 90, 84, 380 (for just a few miles), 81, 77, 26, 95. On this route, you NEVER touch NJ! Yes, weather might be a bigger concern on this route. The toughest hill I remember is on 77 crossing the Smokey Mts.
Regarding the question about the Garden State Parkway (GSP):
According to the toll schedule at http://www.gspkwy.state.nj.us/, "Heavy Trucks (3 1/2 tons or more, 6 tires, or 3-or-more axles) prohibited north of Interchange 105." This is a section from 287 (from the Tapenzee) to well below 95 and the Jersey Turnpike. I've been on this section in a car thinking about a motorhome; it just won't fit. The toll booths and lanes in this area are very narrow. While it's hard for an RVer to know when the "Truck" laws and signs apply, in this case I believe they do.
So, from the perspective of the GSP being a route from New England to FL, the part you would want to take is not available. On one trip, we stayed on 287W as it does eventually get back to 95 near Perth Amboy but this was a long way around.
Note also that NJ is one of those states that if you are more than 2 miles from an interstate or other federal highway and you are over 96", you are breaking their laws (not that I know of anyone stopped). Note my earlier response: I skip NJ in my motorhome.