Best place for 12

[Mojorisin]

1. Hit North Ro or West Commonlands and get a derv group, or kill spiders/scarabs.
2. Hit Oasis and get a orc/croc group. (You'll be a little low, but still able to get a group I'd say)
3. Hit Erud's crossing and farm wisps. Greater Lightstones will get you some spending money.
4. Hit West karana and farm some bandits.

That's all I can think of off the top of my head. North Ro and Oasis will be your best chance for groups.