By all means, go any way OTHER than Exit 417 (Rt 66)!!! Unless you are arriving before 8 am in the morning during the week, take another route. The traffic can be horrendous.
If you are coming west on I-40, get off at 411 or 321, whichever. If you are going into Gatlinburg, take 321, which will take you to the main intersection in Gatlinburg. NOTE: DO NOT ATTEMPT TO drive a MH, nor pull an RV through this intersection. Most of the campgrounds are before you get to this intersection. This is the downtown area and the roads are very, very narrow.
If you are going to Pigeon Forge, take Rt 441, 411, 25, 70 and follow 441 into Sevierville to mile marker 17.3. Take a left at that intersection, which is Veterans Memorial Hwy, which turns into Dollywood Parkway. It goes by Dollywood and comes out at traffic light #8 in Pigeon Forge. You bypass such much of the traffic going this way.
PM me if you have any specific questions.