You can teleport to the hollow world and
tackle those quests, you can take on and clear floors in the main
dungeon, you can take
special side mission requests (in both the
dungeon AND the hollow world), you can help out other players who email you when they get into trouble, you can buy, sell and craft weapons, you can pick partners and even foster a little romance with them and, of course, you can do plenty of that sweet, sweet level grinding.