It's crazy. We have a 2nd home in Ellijay. Bought in August 2018. Zillow estimate now is
more than double what the Zillow estimate was then.
I've gotten two unsolicited offers for much more than I paid. I think the Zillow estimate triggers a lead to realtors that the owner is getting an estimate on the selling price. And I've only had the place 3.5 years. It's unreal.
To answer the OP's question:
Jasper is about where the mountain views begin. 30-40 minutes from Cobb County.
Ellijay is about an hour from Cobb County and is rural with very nice views but has gotten pricey. It's about to expand big time and the locals aren't happy about it.
Blue Ridge is really nice views but an hour and a half from Cobb County.
The further North you go from there, the more isolated but with prettier views.