Go to the graveyard when your supposed to for the quest after you get all the armor for nostro go to the next area there will be undead spawning in the bunches so take out your solus greatsword for fastest kills make sure you have a good physical sheild lvl ( i have max willpower max physical sheild and just enough physique to weild the solus greatsword) have a lot of will potions and some not much heal potions turn on the shield and start swinging i got to 200k exp here easy
btw you get the solus greatsword from upper bowerstone after the arena i think its like 60k gold (very worth the buy)