Play both concurrently, and recreate the buildings you like from DQXI in DQB2.
Yeah, you can definitely play it for as long as you like, but the early game questing/tutorial stuff actually works against it in a way, as by the time you return to the main island and set about learning yet more new mechanics via the mini quests, you've already been playing for hours (and this is where Nate had his fill). Kind of a double edged sword really, because you want the added depth etc but actually fitting it all in is a mammoth task.
Doing the 'rebuild the farm' extended tutorials you mentioned. I have wondered about the starting island - the friend I left behind would have surely starved to death by now.
For those with an open mind, wonders always await! - Kilton (monster enthusiast)