Coming west on I40, just take the marked detour for oversized vehicles. You can either get back on 40 west at exit 424, continue on through Dandridge and get on at the 417 or you can turn onto US70 and travel the backroads all the way to Downtown Knoxville.
Coming east, the best detour is to either exit at either 415 or 417 and go through Dandridge and get back on I40 east at 432. I can confirm that it adds no miles to your trip and takes only 5-10 minutes longer than the interstate.
The construction project was scheduled to take 2 years. They are about 1 year in.