mitsu

Best answer as chosen by Asker / Ratings
This game's storyline is pretty linear. Not a lot to do once you have finished it.

You can't get to vale for the whole of Golden Sun: The Lost Age. Are you sure you are not playing the first Golden Sun game? I'm confused...

Lunpa fortress can only be gotten to in the first game 'Golden Sun'

If you were playing Golden Sun: the lost age, then Lemuria is part of the story line, so you would have HAD to go there to complete the game!

I will assume you are actually playing the first game.

1) I don't think you can get back into vale after completing the game.
2) You go to Lemuria in the second game.
3)Lunpa fortress is east of Vale. In Lunpa. You need the cloak ball to get in there. You receive this when you ask for it from Babi, after you have saved him, and after you have completed the colosso.
4)the djinni are hard to find, and I suggest you use the help of a walkthrough on the subject to find them all. Make sure you know which game you are looking in first!