there is a mail service that has offices in Atlanta, that can provide you with a physical address, but like was warned earlier, taxes that are locally based are higher in Atlanta. Traveling Mailboxes.. is the company..
UPS centers also provide mail service, and there is one in every town that is medium sized or larger.
I will stay with GA when I start fulltiming, but am not sure who I will use for my mail. I will use family farm for my permanent address. Very Very low cost county... actually one of poorest in state.