We just spent a week this summer in the Smokies north of Pigeon Forge. I like to day trip through that area so we have been around Gatlinburg many times. I have not camped there in the travel trailer so I have no reviews for campgrounds.
In general I love the Smokies. I think the Great Smokey Mountain National Park is fantastic for sight seeing or picnicking.
Pigeon Forge, on the other hand, might be where I have to spend purgatory. The kids love the mini-golf and go carts, gem mining and the upside down house - but travelling through town can be TERRIBLE traffic. It's literally a tourist trap, with the traffic lights being timed to force you to stay there as long as possible. First time I drove through there was on my motorcycle in the pouring rain and I sat in traffic for over an hour trying to go 10 miles. Not a happy camper. Gatlinburg is similar, but it's a smaller and prettier area so I don't mind it as much. Gatlinburg is easier to park and walk around where PF requires your car.
In Gatlinburg there is a distillery called Sugar Mills that makes and incredible apple pie Moonshine. Highly recommend you get a jar while you are there.
As someone else suggested, Ripley's Aquarium in Gatlinburg is much cooler than I expected. We had a cub scout overnight trip there and got to sleep in the tubes through the shark tanks which was awesome.
2015 Jayco Jay Flight 32BHDS Elite
Sold - 2007 Jayco Jay Feather 19H
Curt weight distribution hitch with sway control
2004 Ford Super Duty f-250, Bulletproofed 6.0 Powerstroke diesel with SCT chip