I would suggest watching some youtube videos, come up with your own variation of someone elses script and practice it until it sounds natural.

In reality to be successful in real estate you need knowledge of real estate principles, real estate finance, real estate law, and real estate practices.

Are there any particular management practices or tools that have proven effective for rent-by-the-room setups?

100% financing is possible but not practical.

I'm looking for insights and best practices from fellow lenders and financial professionals on how to effectively manage borrower relationships.

If you really want an answer you can confidently rely on you'll need to engage an attorney practicing in the state the property is located in and the state of residence of your grandparents and have him research the specific facts of the case.  

How have they impacted your business practices and client interactions?

Could be SEO, admin work, investor relations, social media management, asset management, etc.

Those places practically give rooms away to get people on the gaming floors.

I have seen a few try to get started over there last several years, but none seem to have survived (or are really bad at SEO and marketing) since I was not able to find any the several times I have searched.That being said, I know Cadre has launched a secondaries market for their own investment offerings, but that is limited in scope to Cadre positions, and is currently closed anyways and will be "re-opening soon".