We started from Sarasota and made it South of the Border(cheesy but passable for one night) the first night and decided 6 or so hours a day would be better. Cherry Hill park in College park MD was a perfect place to stay for DC. A bus regularly goes to the metro or the bus tours will come pick you up.
Koa Savannah South is a great park. Get a lakeside spot with view of swans. We only stayed one night but if we could have we would have stayed two and done the Old trolley tours for savannah. It looked like they came to the park and picks you up. We did not have a Toad so we had to plan ahead.
We stayed at Little Buffalo State Park in Perry County PA. If that was an example of PA state park, we would recommend them(and they have an App, same as FL state parks. Sorry if this is jiggly we are still rolling. I am off driving duty right now ;)
Let me know if you have any questions.
Heidi :)