The main guide lines focus on it being on a permanent foundation (Concrete slab), Hurricane tie-downs if you are in FL, GA, LA and a few other states, must be a double wide and not moved from another location.

This is so important to avoiding massive issues when you ultimately begin sitework.

(additional info: changing the stairs or getting new ones would be a massive undertaking)

The rental unit was probably built as an addition to our part it’s on a concrete slab, no crawl space. 

We just experienced a period of massive real estate appreciation and the forums will continue to dismiss it's importance.

I have done massive amounts of research on owning and operating coin laundries.

Been watching this market a little bit from afar, and can’t believe the massive price cuts!

I’m fine with this, for now, as a long-term investor.I don’t believe our current situation would enable us to qualify as Real Estate Professionals, which would result in massive deductions.

Or can you line it with concrete, and make it 30 feet deeper, with a smaller footprint, or put in several smaller ones?

I would list with Redfin (lowest commission 1.5%) and massive exposure.