North Georgia travel

If you mean I-81, I suggest 81 south to Johnson City then head toward Asheville NC (19/23). From Asheville, take I-40 west to the Waynesville exit (may be 27 but not sure) This will be US-19/23/7 toward Cherokee. At the Sylva (area) look for US441 south toward Franklin. Use the Franklin by-pass, this will still be 441. Follow that south to Clayton Georgia. From Clayton you can head to any number of small and delightful N Georgia mtn towns with some pretty neat CGs.
We like River Vista in Dillard (for convenience) when in that area. You could go over the mtn to Hiawassee (easy trip) to River Bend CG or maybe Moccasin Creek SP on Lake Burton near there. Georgia Mountains Fairgrounds and RV park is also in Hiawassee on Lake Chatuge. Just Google for RV parks in the area.
If you want to go thru Atlanta, you can go to Gainesville, Ga on US 23 and go south on I-985 to I-85.
I might avoid the hassle and stay on US 441 through Commerce, Athens, Madison, Eatonton to Macon and hit I-75 there. Better drive IMHO with a lot less traffic, better scenery and less frustration

This was sorta wordy, but I hope it helped ;)

We use to love taking day trips to Helen when we lived in GA fulltime.

We would come in from the southern side via GA 400, through Dawson and Lumpkin county, which will be the fastest and easiest way for you to get back on I-75 heading south through Atlanta.

If we are towing, we come or go to I-75 through Canton, GA heading to Cumming. From I-85, we take GA129 and go right through Gainesville and have no problems driving through the city.

My kids have camped at Unicoi State Park, but that was in a smaller 5er.

We love North GA so much, we bought an RV Lot sight unseen in Blairsville last year. Drive to BVille, we take GA575/515 through Jasper and Ellijay to avoid GA129 north of Helen. Road is Too winding even when we don't tow.