There's venture cave. Important prep was GG, and finding wonnafyt helped wiht XP and exploration a lot. Careful with balanced dagger, don't pick it up too early. In case of no yendor, make good use of the randomly spawned drac altar such as I did here, but save it to for leveling up to 10. Impossible to do without humility pretty much so GG is autoprep.
Also, hitball subdungeon helped me here, as it always spawns enemies of the same level. If a subdungeon spawns enemies with a level higher then 1 or 2, make sure you kill them at appropriate times to help your XP gain.
Deffinitely practice it here before you try it somewhere else, it's tricky!
Also - I whish bandits and all the other humans had different... clothes or whatever. I know they all share the same boss trophy and all, but being able to tell them apart would be a nice thing since berserkers and bandits are simply not the same monster, and the hittball guys aren't any of those either.