Updated to include the 'Monkey Ball' quest from Dragon's Jewel, worth 300xp.

As I said in the OP, the quest does not specifically mention a 300xp reward, but upon completion, you do get it.

I have not completed the entire Karin questline yet, nor have I even gone into Kraag Tombs, so once I get around to it, I will include those two quests as well.