Easiest exit to Glen Allen, VA Supercharger is exiting at I-295 West, stay on the ramp, and exit US 1 north. Reverse the direction to I-295 south. While it is shorter distance on I-95 through Richmond and Petersburg going I-295 is much less traffic.
Clarks Inn at Santee is good place to eat and charge. Savannah to St. Augustine is 162 miles. But there is not much in Savannah Airport. I found that if the Superchargers are 110-130 miles apart that if you start with a full range charger the next two chargers can be quick 15 minute chargers before having to charge longer to 'fill-up'. If planned right with meal stops it makes long distances without delays.
Port Orange is a good place to eat and get a full range charge unless you have a hotel with J1772 charger.
have fun!