MMm we had this a long time ago i remember discussing this.

10-14 Shakrami Maze, Worms and later weak Gobs.

15-18 Korrokla Tunnel for more Worms.

18-23 Saruomange Champainge, look for the nitch near the right rock as you exit Jeuno and chain Beetles.

24-25 Qufim, Aggro from Wights and Giants are less of a threat and its much more viable to exp there now.

25-27ish Battlia Downs, camp bunkers and just kill ITish mobs.

27-30 can be Rolanberry Fields, chain gobs and the weaker Quads.

I only recommend the Grotto if you know how to get there first :P its confusing so i put ginger bread cookie trail on my map to get there lol.

So yea i lvled through these and try to avoid the mainstream lvling areas especially confusing Kazham.