So I made my first shopping trip to Target and Petco to get some (many) of the things I needed. I even found a natural wood shelter that I think my hedgehog will like - refuge from the world of plastic. As I started putting everything in the plastic bin, I realized that the exercise wheel takes up a lot more space than I expected! Now I must use my engineering skills to make a tunnel between the main plastic bin and the secondary (green) plastic bin. According to my measurements, these two bins should still fit in the HOL storage cube from IKEA. I also realized that the small animal corner litter pan is too big to be in this size of a cage - so I plan on exchanging it for the smaller version, and I will try it out to see if it'll work (if not, I guess I'll get a small rectangular one).