Leveling place?

[Cho]

Paradise (island NE of Orcus Village):
Fast auto-overwhelmed battles for 1/2/3 lvls

There is also Formation 14 - Maidenator 13 (Forgotten Village - Secret Arena - Sister-in-Law)
Gives:
EXP x2
GOLD x1/2

[Valius]

I leveled up at the trial tower without purchasing the key, equipped the attract jewel, several experience jewels(20%) and when the exp got low, raised difficulty. On expert the auto battles get me between 2m to 6m. I'm sure if I added titan gems it would net more. I'll eventually buy the key but I'll be cheap for now