It's going to take you longer than you expect! There is a lot to see and plenty of opportunity to make a stop on the way toward the Zero Mile Marker.
The journey is officially 163 miles (roughly 264km) but plan for about 4 hours or more in actual travel time.
That's because it's a single lane in each direction and the speed limit might average only 45 or 55 mph, with dips as low as 35 in more built-up areas.