I thought this could work by giving the player an item, for instance a note entitled, "Quest - Fargoth's Hiding Place", and removing the item when the quest is completed. This way players would be able to easily find out which quests they still need to complete, just by looking through their inventory. It could literally be that simple, or it could be more complicated - for instance, these "Quest Notes" could give information on where the player got the quest, what the player has to do, or where the player is up to in the quest.
Let me know what you think
- Danjb