My experience has been that although I outline the requirements for tenancy in my properties, both brokers and PMs still send people who would qualify for most property owners but do not meet my outlined criteria; and then are SHOCKED when I reject them.  

I think we could transition this from a medium term rental property to a nightly property and do well, but that would require more time, money and effort from me which I don't have at the moment as I have just acquired a large campground.

I did do a precursory investigation into what requirements are and it looks like there might be some zoning restrictions, as well as permits required.

I have been able to find a couple of options for this setup though, they just require separate leases for each room and sometimes 2-3 months of rental receipts as well. 

In Texas, as a licensed agent, you’re generally required to use TREC-approved forms for real estate transactions unless an exception applies, like (I believe) leases longer than 1 year or where no TREC form exists.

Despite the guru fed “misinformation” about all these under market price deals, they are actually very rare and require (1) the investor recognizing value that the seller and the rest of the market misses or (2) a seller with a need for an immediate sale and a buyer with the CASH immediately available to conclude a very quick closing usually forgoing inspections, financing, and other contingencies. 

Your $80K HELOC can serve as the down payment, as most lenders require 20%-25% of total project costs upfront.

Lots of people who have trailers don't own the property they are on and sell them.As for the owner of the land expecting tenants to do repairs-there shouldn't be many repairs required to the land, just the trailer that is on it (which your grandmother owns and should be responsible for maintaining). 

Even a single family builds can vary significantly based on site conditions and required structure/design.

If it crashes hard enough, it impacts your personal finances, your relationships, and even your mental/physical health.With the exceptions of politicians and so-called charities, building wealth typically requires sacrifice and time.