I haven't gotten far enough to make a nether portal, doing it that way will have to wait until I get more challenges finished.
The shop can be tiny, just a wall right there on the little island, the beginning chest items so people don't just buy what they need in stack and cheat the challenges. That way, derpala can still make profit off of what she is selling at her shop as well.
I had to reset my island a bunch of times in the beginning because of something silly like messing up my cobble generator and not having any more lava (a few times), and that shift button gets me in a lot of trouble.