I had that same hwy32 on my route last Summer but that day ride was a rain out so I didn't get a chance to go down it. But it all looks paved on streetview. I'd def give it a shot.
May 7-10 is perfect! During the week, not on the weekend and school is still in session so no big giant summer vacation crowds. You should be good to go!
Route improvement suggestion: Just before you get to Tellico Plains, TN take
HWY 360 north to Vonore, TN instead. Very scenic valley road with lots of terrific sweepers. You'll like it!
The rest of your loop is a can't miss.
Route improvement suggestion: Just East of Townsend, TN take
Little River Road (E. Lamar Alexander Pkwy as noted on the Googlemaps...turns into little river rd) and ride along the beautiful river and visit
Cades Cove as well which is right off this route.
Also on HWY28 about 7-8 miles south of Deals Gap in NC take the short spur and ride across
Fontana Dam which is also a great photo opportunity.
Lastly instead of taking 441 from Dillsboro, NC to Franklin, NC...find Cullowhee, NC just over on hwy 107 (just SE of Dillsboro) and take "Tilly Creek Rd / Ellijay Rd" from 107 to 28 as a cut through. Terrific scenic road...no traffic...valley & then twisty section as well.
Those are my suggestions. Other than that you'll def like both of these routes you've set up. You've done good. Let me know if you can't figure out these suggestions and I'll be glad to help.