Using the admin tool to add pathing doesn't work out so well.
There is no way to tell what the terrain is like so you end up with npcs floating across the screen in mid air (load up my original moving npc DB for an example).
The only way that I have been able to successfully create moving npcs and keep them on the ground , is to add the grids and paths while in game.
You also need to make sure that if it's hilly terrain that you don't use random waypoints or you'll wind up with the same floating npcs.
For hilly terrain I use the circular waypoint setting and make the npc circle back around to the original point and start over, that keeps them following a set path so that they can hit each waypoint in turn and keep in contact with the terrain surface.
Probably not what you wanted to hear , but I've been working on this for several months , and this is the only solution I've found.
My Moving NPC DB will be available to everyone when it's finished (probably be released in increments over time) so ALL can enjoy moving npcs.
If you'd like to see the difference between the original movement and the new method , load up my original and run it ( floating npcs and zone crashes) , then log into my test server and check out the new movement (smoother , not floating , no crashes).
The test server is the MyWorldEQ npcmov test server.
Hope this helps a bit