I would say coifs for faster XP, but Flax sells if your after the money, and also helps your fletching skill if you are after skill levels. To be honest... I haven't finished Lunar, So I'm not sure.. but if I had to guess, you'll be able to come back... It seems to be the way you get to lunar island. Also, I think its better to pick the tars alone for speed.. Picking the tars is like picking flax... when the barrel empties for you, its empty for everyone (but the refill speed is pretty fast). You could bring a friend or two.. and just have 1 person at each barrel.. but it would probably be more efficient just to have your firends on different worlds picking their own 3 barrels, and just using PM to chat. I'll add ya... But I'm not on very often lately (in the process of moving). I should be back to my regular playing schedule in a couple weeks. Yes, you can come back after you finish lunar. There is also a caged suqah after the quest you can train on. :D