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. 

Yes, Kansas City has tenant-friendly laws, including:Stricter eviction processesLandlords required to meet certain habitability standardsMore tenant protections against retaliationIf you’re unfamiliar with local laws, a PM can help navigate compliance and avoid costly mistakes.Final Thought:If you prefer a hands-off investment, a good PM is worth the cost—just vet them carefully.

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. 

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.

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.

Set clear and consistent application requirements so you can base your decisions on solid facts.