I solo in in this manner:
GC: 30-38
CP: 38-40
Uruga: 40-50
AEW: 50-54
FOS: 54+
Also if you have friends that can make t3 defense/vitality you can start duoing with a level 40 archer (with those 2 scrolls, possibly t1 aim, green gears, and an endure) on blue clovers (kills amazingly fast). You will reach 50 along with the archer in less than a week from 40-50.
Edit: the duo target should be blue clovers, the path up to the FOS gate should be a safe spot as long as no trains come by (a violation anyway). if you're mobbed you're kind of screwed without other clerics nearby.
