Are you going from W Washington D.C.
just one way to Fort Lauderdale
or is this a round trip. Because there are two possible scenic routes - the mountains or the seashore.
If you want the mountains, (which I guess you do since you mention the Blue Ridge) from DC, you can go over to the Skyline Dr
and follow that all the way to the Blue Ridge Parkway
and then you can follow the Blue Ridge Parkway all the way to the Great Smoky Mountain National Park
This will be one long day or two shorter days. The Great Smoky is partly in NC and partly in TN, so from there, you can go over to Gatlinburg
down to Talladega Superspeedway
and then to Fort Walton Beach
Then you can follow the coast around to Tampa
and all the way down to Naples, Fl
and then go across to Fort Lauderdale. This avoids the congestion around Orlando and Atlanta although you do go through Birmingham (Alabama)
The seashore route would take you down US 301 to La Plata
and then down US 17 to Gloucester (Virginia)
(which is a nice littel walled historic district), and then on down to Virginia Beach
From here you could go to Elizabeth City
and then hang a right and go over to Nags Head
and visit the Wright Brothers National Memorial
. Then go over to Plymouth (North Carolina)
and "Little Washington" i.e. Washington (North Carolina)
and you can follow US 17 all the way down through New Bern and Wilimington NC and Murrells Inlet SC to Charleston
You could go to Savannah GA and St Augustine FL on the way to Ft Lauderdale.