I depends on whether you can beat Wooly or not. If you can't, then just repeat rooms and get the clearing bonus. If you can, then just keep beating him and continuing the game and repeat.
If you kill or destroy or defeat Wooly you get 2500 xp and then you can play on whatever your level is the game again like your level 40 you defeat Wolly play the campain again then you are like level 40 when you start but for the low levels in de caves there a big gap where alot of crawlers walk down it mite help if you find it.
Just find tougher enemies (Make sure you're strong enough to fight them) and kill them for the Exp. and keep going in and out of that room(s) and keep fighting them as they respawn for experience and since you're leveling up your HP should stay reasonably high
Yeah,if you are trying to defeat Wooly go to the cave and head all the way to the right and enter the door. Climb down and and enter the door left from Bobbington. Then go down to the next door in that room. You should see a giant pit with a lot of monsters. Grind there. If you beat Wooly just grind him.