Or buying a large house with enough restrooms where you can put dividers up to separate the space and/or upgrading the garage to an ADU. 

I have a guy who has an avionics business that wants mezzanines built for office space, technician training rooms, rest rooms and etc..You actually hit on a great opportunity that is currently out of my budget limits and that is Air Park development.  

How does Air B&B know you didn't install a camera in the rest room?

Interestingly, they've recently negotiated a re-purchase price with us IF we bring new funding to the table.The rehab is required for several reasons: (a) correct the damage the bank has allowed to happen to the property improvements these past few years (known problems include completely destroyed pool makeover; wild animals living inside the residence; flooring missing in sections of the rec center building; destruction of the decorative main entry gate mechanism; lots of dead landscaping; as well as latent defects not known to us such as working plumbing, HVAC & water services) AND (b) expansion & upgrading of the accommodations (converting the private residence to a 2-story lodge with the restaurant/bar, reception/check-in, movie room, public restrooms, gym/sauna/steam room/massage therapy room; enlarged pool & deck area with climate-controlled cover for year round use; conversion of former restaurant/bar building to a general store selling venue collectibles & wearables, selected pre-packaged foods, sundries, RV & camping items, bagged ice & a propane refill station; construction of a free-standing event center; free-standing cabins; enlarged & upgraded RV park with its own small restroom/coin-op laundry building; outdoor activity areas; new landscaping & fencing; new parking area & entry drives (personal car & RVs).We know our target audience having created and operated the former version of this resort for almost years creating an initial membership base numbering about 1,100. 

I ended up switching the fan switch to a motion sensor switch so that it automatically turns on like the ones in public restrooms.

This would include about 1,000sqft of basic office and restroom and the warehouse area being semi heated only.

@Michael Dang   I recall reading something not too long ago that said the huge warehouse market was overbuilt in Houston, but the small light warehouse market was underserved.I assume you're talking about the smaller projects with a rolling door and a big open space with a small office and restroom.

The following items were neglected in order to save money, as examples: our hedges all had extreme white fly damage, wood rot due to water damage and putting off painting, our pool restrooms have massive holes in the roofs and we are in the process of reconstructing 2 of them.

I have designed a few public restrooms where I typically use concrete block and stainless steel. 

Additionally there is an issue with the subfloor in the bathroom and it is no longer safe to use the restroom.