You do know that High level players will be far more willing to mentor right? First because they get void shards either way and second because they get a HUGE AP XP bonus for mentoring, and the farther back they mentor the better.
As for the zone locations... they are marked on the Map... but like with every other part of the map you accually have to GO THERE to remove the fog.
Once the fog is removed the zone will be marked...
As to why they are scattered all over norrath... it's because thats where the zones belong.
Mistmoore's Sencutary belongs in LP, Nagena's Workshop belongs in LS, Mirigul's belongs in EF, and Befallen Belongs in CL