Sounds pretty similar to a system I'm working with at the moment.
With my system I've pre calculated most of the route data, so picking the next place to visit (ppoint in the case of EQ), all thats required is a lookup.
Only requires a small amount of memory because of the way I've grouped it.
The grouping is also automatic..so it seems feasable that you could just place points on the zone, and then let the code decide howoto group them.
Open areas will need o be marked though
Hmm, perhaps what points their connected too would discribe weather they where in the open or not?
Lots of paths for open areas, and only a few for normal ones?!
Anyways, if you want some assistance, then let me know