Well it's depends on which side. If you are going to stay on the Tennessee side I can't help. If you are gonna stay on the NC side we stay at http://www.mysmokymountainvacation.com/camp-smokemont.html there is no hookups in the national park campground It's near Cherokee NC. In Cherokee there are a lot of campground to choose from.
Got this from another post here on these forums. Check it out if you haven't already. http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27604179.cfm
The is another camp ground just before you go into the Smoky Mtn Park from the Townsend TN side of the park. It has Electric service and creek side camping spots... Lots of shade here...
Alot of folks like the Pine Mtn camp ground which is close to Pigeon Forge but on the south side out of the high tourist traffic and on-goings...
We have stayed at the RIVEREDGE RESORT just as you enter Pigeon Forge from the Gatlinburg Side which is a real nice camp ground. It also has the Trolly Stop on site.
Camping inside the Natl PArk is where we really love to camp but just be aware they have only have bath rooms and water you can carry to your camper. No hookups. ELKMONT CAMP is where we camp alot inside the Natl Park. Driving the PARK road does have a few real sharp curves with overhang which you have to watch very close driving the higher trailers thru there.
In Cherokee we liked Happy Holiday campground. We chose a back in site on the creek. In Sevierville TN we like River Plantation. It's on the north end closer to I-40 and the easiest to get to. Trolley runs from Sevierville to Gatlinburg.
We have stayed at Twin Creek less than 5 minutes to the north of the Gatlinburg strip. Only 10 min to the national park from there. Great people own it, and it is nice and quiet there. Give it a look as well.