I have quite a few quests on my log, should I complete them before getting spirited away? I guess I could use the treasure and experience before starting a new area...
No need. The area you go to is a really short little interaction and you'll end up going back there a few times. It's kind of a little home base. As you do more stuff in the game, more unlocks there. You can leave it at any time after the initial interactions there and it'll put you right back in Cyseal where you were.
It's literally just a way to introduce you to the homestead.