When on the Blue Ridge parkway (North or South) take US52 South at Fancy Gap. This will take you to Mt. Airy. You can take either state hiway 89 or US601. Both will take you to downtown Mr. Airy, go left or East at either. I would take hiway 89. If you take US601 it dead ends at Main st and you can park at the post office, plenty of room for your RV. Hiway 89 goes thru Mt. Airy, but when you past Moody funeral home there is a large parking area to the left, turn left at the traffic light. Snappy Lunch closes at 2PM. not sure about the Andy Griffith museum hours.
Lots of eating places, the best in my opinion is 13 Bones on US52, closed on Monday. We eat there every week, usually on Friday.
If camping is an issue there are two private CG. There is also a Wal-Mart on US601. See campers there all the time.