We have stayed at both the Twin Creek and the LeConte Vista campgrounds in Gatlinburg. Both are on the trolley route, and one was closer in to town, I think it was Twin River - and that was very convenient. If you have children, riding the trolley is alot of fun and prevents you from trying to find parking - which is at times difficult.
We always go into Pigeon Forge, but the traffic is very bad there, and I haven't found a campground there I like - most are in town limits, and there is always some type of car show going on, so I think it would be very loud. Both of the campgrounds I mentioned are quiet, and Twin Creek has fishing, so we like that atmosphere better.
Have a good trip!