The PVI's point storage capability is:

2 Airfield
6 Waypoint
10 Nav-tgt
4 INU update

With the six waypoint locations you can string them together in any order to create a custom route. By default the route is the mission editor path starting with the first non-takeoff location and ending at the last non-landing location (or six). It took me a while to realize that the changing of WP sequence for route is simply changing the sequence. The waypoints and their L/L coordinates remain.