Here is another second for Pine Mtn RV Resort. If you are afraid to drive on curvy roads, plan to get to Pigeon Forge on a weekday, during the day. In the evenings and especially on the weekends, traffic can and will be horrendous.
Take your vehicle into the Great Smoky Mountain National Park. Go to Cades Cove early in the morning (check when you can drive in), sometimes you have to bicycle. Do not under any circumstances take your motorhome into downtown Gatlinburg or into any of the national park roads if you are not comfortable driving winding, narrow roads.
Elkmont is a very nice campground in the park, but it is up on the mountain and it's a 2 lane road getting there.