I am also in Georgia and even with no cover, one window open, roof vents open, fantastic fan set to come on when it warmed up, this year I ended up with the worst mildew I have ever seen. No surface was unaffected.
I put on a face mask, unloaded everything, and sprayed and wiped everything down with lysol. BTW: my face mask included charcol filters which is a good thing. A large amount of lysol in a confined space is INTENSE!
Note 2: Turn off all pilot lights and the propane detector and/or disconnect batteries and power. Otherwise you will be setting off the propane detector