I started grinding from lvl1to 50. I bought the challenge map then played it up until now. I am now lvl 75 and im grinding in lvl 102 floor. My advise is, if you want to lvl up faster using barbarian, i suggest you use the necklace that has WRATH nature in it and use items that have explode options, double damage and try to get a weapon that has ascendant option (weapon plus another item to get the 50% weaken option) and items with weaken options. It will make your grinding faster because all you have to do is run around the enemies and they will just explode!
This is what I did in the earlier days of DQ run around with Ascendent Build just minus the Barbarian.
barbarian drops at floor 102?