(Some people have taken tiny house road worthiness to extremes. See Tiny House, Giant Journey and Tiny House Expedition for two examples.)
We don't have plans to move our tiny house, so we were able to make it more spacious with a 12-foot width. Should we decide to change locations, we would need to get a "wide load" permit, have our travel plans approved and hire a professional company to do the moving for us. But, fortunately for us, we have the blessing of our dear friend and landlady Susan, who wants us to stay where we are. We designed our structure with this specific site in mind. We love it here.
So, why the wheels? For us and many other tiny house builders, it's a building/zoning thing. Ours is a legal "travel trailer". We have a license for our travel trailer, and we pay county property taxes on it.
Building this same house on a foundation on this site wouldn't adhere to the building code (too small), and it would require a zoning exemption (more than one permanent home on the lot). Hence, the wheels. In addition, we have a legal address by maintaining our own small living space within our friend's home. We contribute to her operating expenses, alternate hosting happy hour, keep an eye out for one another, and, as a result, all of us better enjoy this beautiful, rural setting. It's an idyllic set up.
The wheels beneath our house used to be most visible on the side of the house that our friend looks out on. No more! We attached lattice to the base of the deck. In addition to hiding the less-than-attractive underbelly of our structure (with its cinderblocks, jack posts, wires and what not), the lattice will eventually support grapevines. So, it's not just ornamental; the lattice will play its part in our slowly expanding mini-homestead.