We are heading down to Florida soon and since my trailer is winterized, I don't want to put water in the tank until we get further south.
Santee state park might fit your bill? We usually stop there from NY to fill. We do carry about 6 gallons of water to use and if it is really cold out we use the toilet but flush with the pink antifreeze. Flying J will be noisy...people coming and going all night. South carolina will allow overnight parking in rest areas even if it says no...we asked a worker once. Also exit 57 in SC has a walmart which could be more quiet.
There is also a new welcome center in Georgia...they are always a good choice....park away from trucks though.
Hope this helps.
Donna