Combat levels, prayer levels, money, and good items
Get a Brass Key by any means necessary. You can find them far into the "dungeon/mines" of Edgeville. Go to the locked little house with a ladder leading down inside in between Varrok and the Barbarian Village. Use the Brass Key with the door providing access. Take the first turn to the left into a close room (with a gate) filled with giants (level 36). The giants give good experience, drop big bones (better for prayer than normal bones), money (up to 47 GP dropping at a time), and good items (steel and iron items, gems of all grades except for diamond, and all runes). Note: Bring a fly fishing rod and feathers to fish for some food when down there.