You can raise Peace to about 30 by moving between these areas. This lets you focus on Fame.
Fame is important if you want the best party members. Some require 45 Fame!
Economy will save you gold in the first playthrough but after that it is not a concern.
If you feel like buying a "Special" item (with real world money) buy "Chain of Destiny" so you can turn off encounters. Trust me, fighting hundreds of slimes at level 50 is boring.
I think a good idea is to get the so called "Tiger man". Good HP and attack power. You will know when you get the Judgement.
Oh save before passing any Judgement!!