That is the way to go into PF and back out, but you will don't want to go through downtown Gatlinburg in a MH. The streets are narrow, crowded and NOT made for large vehicles of any kind.
To get into the Elkmont area, go I-81 until you run into I-40 (across the TN line, not near Christiansburg). Head east on I-40 for several more miles to exit 432A (Newport exit). At the intersection, take a right, then the FIRST left onto Rt 411. This will head into the back side of Sevierville. Go approximately 15 miles until you get to traffic light 17.3, where you will take a left onto Veterans Memorial Highway. After a few miles, it will turn into Dollywood Parkway. You will pass Dollywood and come to the end of that road. At that intersection, take a left toward Gatlinburg. (You will have bypassed all of the traffic of Pigeon Forge). Take the Gatlinburg bypass and head on toward Sugarland welcome center. Take a right just past the welcome center and you will be on your way to Elkmont without hitting all the traffic in the PF and Gatlinburg area.
Just so you know, Rt 411 is a two lane, curving road, but is used by many RVs, semi-trucks each and every day, just be aware that there are some large curves and pace yourself, you will make much better time on this road than sitting in traffic on Rt 66 coming into Sevierville.
Another heads-up: On Rt 411, just past the Bush Bean plant, 411 goes off to the left and Rt 92 goes straight ahead. Do NOT follow Rt 92!!
We travel this highway each and every time we go to PF or Gatlinburg. We are pulling a 36' fifth wheel.
When leaving Elkmont, I would just re-trace my steps to I-40 and head on east toward Asheville. Rt 321 goes through downtown Gatlinburg and I would avoid it in a MH. We usually try to avoid it in our Ford F-250 pickup truck because of the width of it with the mirrors. If you have your toad out, drive through and check out the narrow roads and then you can make that decision yourself.