Nethack grinding for level 14

I decided to get into NetHack for the "junethack" competition. I'm loving it so far. I've finally made it safely through the early part of the dungeons. I've finished Sokoban and gone through Mine's End. I made it down to my quest. I'm level 12 and have been grinding forever to get my level up to 14 to go on the quest.

I've descended 10 dungeon levels past my quest and back up again. I've identified my potion of gain level, but searching for two of these will probably take longer than just killing stuff. I've run into no wraiths.

Are there any tips for making this part go faster? Do people usually skip the quest and come back later? I imagine this will take hours to just wander around killing enemies until I get up to 14. I'm a dwarvish valkyrie if that matters. I'm also playing the Nethack4 variant if that matters.