"There may be a detour along the way, unless they've replaced the road that washed down the mountainside!"
They have. The road is good all the way to Chilowie. I'd allow about 1 1/2 hour for the drive from Gatlinburg, as it's about 40-50 miles to the Dragon, and the roads are not interstate by any means. As you point out, the roads getting to the Dragon are just as much fun as the Dragon (except for the short stretch through Townsend). I live in Maryville/Alcoa, but I agree about the return trip - go back the way you came rather than through those two cities.
Motorcyclist try to run the 11 miles in 11 minutes, but I wouldn't recommend that with an MG. At the '03 V8 meet, the record time in a V8 MGB was 17 minutes - still a pretty scary ride.
If you tend to get seasick, DO NOT ride the Dragon as a passenger. Trust me on this one.
One other word of advice - people come from all over the world to test their driving skills on the Dragon, an many are severely lacking in these skills. It's not at all uncommon to round a blind curve and find a "wanna-be" hot dogging it in your lane, "clipping the apex!"
Instead of making the right turn to Townsend and the Dragon, you may want to go on straight ahead and take a liesurely tour of Cade's Cove, another 11 mile drive on very twisty roads, but at a much slower pace on a one way single lane road through an old pioneer settlement.
Little river road from Gatlinburg to Cade's Cove is outstanding.
Take a look at:
https://www.britishv8.org/2003.htm
FWIW, we will be having thr British V8 2006 meet in Townsend again next year, from June 18 to June 21, just prior to the MG 2006 meet. Come on down for the V8 meet and stay for the main event - get 2 fer 1!