U.S. 74 from I-26 to Shelby just needs wider shoulders and they could slap Interstate signs on there. Once they build the Shelby bypass (R-2707 - no earlier than 2012 for the first sections) traffic will really pick up on U.S. 74 and I-26.
U.S. 64 would be a lot of work, to say the least. I was picturing U.S. 74. Waynesville to Sylva is four lanes divided with limited access for 14 miles, 4 miles of full control from Sylva to Dillsboro, 7 miles limited access again before going back to 10 miles of full control around Bryson City. So, 21 miles of upgrading from limited access to full control of access isn't all that bad to have a complete freeway from Asheville to Bryson City. Then A-9 comes in...
I know they're bypassing the beautiful Nantahala Gorge, but that mountain coming down into Andrews is steep! Not to mention the cost...
A-9 Project Breakdown Map