Not clear if you're talking about a hub-and-spoke kind of riding, or a tour (say from Roanoke or Asheville) into Boone. If you're planning to ride into Boone on the Blue Ridge Parkway, I'd suggest you add a least one extra weekday to allow for rain/fog/clouds (sit that day out). Avoid Asheville (25 on the south to the last entrance climbing up to Craggy), and Roanoke (340 down to 221) except on weekdays between 9:00 and 2:30. Too many people use it as a commute route. Same for the stretch from 421 east of Boone to the second exit west (south) of Blowing Rock.

On a hub-and-spolke, I'd say you could enjoy some good riding on the BRP by driving down to Price Park and see how far south you can ride and still get back by 3:00 (when the high-schoolers and college kids get out / wake up). From Price Park down to Craggy Gardens you'll only have the dedicated leaf-watchers on the road.

There are some pretty good climbs available if you want to do hill training. Shulls Mill Rd. comes to mind, and the Sugar and Beech Mtn. climbs are challenging and pretty. The road from Beech down to Elk Park is narrow, winding, beautiful, and has only local traffic. But you couldn't pay me to ride a bicycle down there from Boone!