The mentioned routes are basically the way I go. I agree with LynneF it is pretty easy to just stay on Wilkesboro until it hits 47. Although one time I did turn on Aerts then left on Washington then followed a dirt path across a field then carried my bike over 2 sets of railroad tracks and ended up in a Banks housing development with a bike trail past the school and local roads out to 47 very near the Banks-Vernonia trailhead, but I only recommend that to very adventurous folks.
Other roads to consider are Susbauer to either Kerkman (very low traffic) or Milne (gravel road) to Harrington to Wilkesboro. And instead of taking Leisty to Wren try the Bagley road loop that goes past the airport. Some of the houses adjacent to the airport have airplane hangars! I think all routes include short rides on busy roads with shoulders but I can't remember anything unpleasant about the ride at all. Also I can recommend a very good sandwhich/coffee shop in Banks on the west side of Main Street, Banks Trail Cafe. All routes, the cafe and even the dirt path I followed are easily tracked on Google maps.