Georgia now operates under a one-time title ad valorum tax law that applies to motor vehicles (pull behind trailers still pay a yearly tax). Basically, you will pay a one time tax based to the value on the vehicle when you register it. In 2015, it was a 7% tax.
As a new resident, you can break the amount due into two payments in 12 months.
Additionally, there is an annual tag fee ($20) and a one-time title fee ($18).
Some counties require annual emissions testing (about $25).
https://onlinemvd.dor.ga.gov/TAP/faqs.aspx
You can plug in your VINs to see the tax online. I'm not sure if motorhome VINs will work. You may need the call and ask.