Before you begin it's worthwhile to know a few things beforehand: The final boss is a relatively simple fight which you are given more than enough supplies to defeat, including 2 prayer potions, and several strength potions that raise your strength by 10. You will likely only use one prayer potion killing the 10 trolls before the fight. It is recommended you bring and have yak armour and your shield equipped before you begin and at all times, as repairing one of the bridges can be dangerous, and running to the eastern side of the northern-most island can be fatal without these items. The quest is also relatively short if you gather all the items beforehand, and you'll likely only need 5-6 good food prior to the boss.