You can take 40 if you want; it is open now. It is also interesting to see how the river gorge has changed after the storms.
However, the route through 40 was never much shorter from CH than going through Wytheville on 81. One route takes you N then S, the other S then N.
If you aren't interested in going 35 through the mountains, and can deal with all the semis on 81, especially near 77 in Va, go up 81 to 77S, then just into NC near Mt. Airy, take US52/future 74 to Winston-Salem/Greensboro, then on to CH. About 5 1/2 hours as long as there are no wrecks on 77 coming down Fancy Gap (the most perilous part of the trip.)
Who are you giving a talk to? Is it an open talk? My eldest, a freshman at UNC, is kind of a science geek (neuroscience interest.) If it is an open talk, he *might* have an interest in hearing what you have to say.
Regardless of how much I hated my time there (and I hated it a lot), it is a pretty campus. Stay out of the bell tower.