I’m new here myself but know the trip from Virginia to Florida well. If you want to avoid traffic, try to avoid going around DC. You can do that by using Rt. 301 south through Maryland and it will take you over a bridge and hook you into Fredericksburg, VA. If he is into Civil War History, there are four battlefields right in that area. If you really want to go off the beaten track and avoid I-95 you can take Rt. 13 south through Maryland all the way down the Eastern shore and cross over the Bay-Bridge tunnel across the Chesapeake Bay. Then you won’t be too far from Williamsburg, another great historical site. These routes won’t be as fast, but it does get you off of I-95 which isn’t fun, especially around DC. Further down, Charleston, SC is a really neat town to explore. I also totally agree with checking out St. Augustin, FL.