In my mind sub to is for short term .. long term rentals is very problematic for many reasons. 

The Long term, after some reserves, I'd like to bring down the assessment costs since I worry that this will negatively impact the property value. 

Long-term fundamentals?

I own 20 acres of land valued at approximately $80,000, and I want to build two short-term rental (STR) units on it.For context, my family already owns two long-term rental (LTR) units in the same general area.

Are there any resources that help explain what type of terms we should ask for?

We do long-term rentals and practice BRRRR on every deal. 

She can use that money to get a hotel room or short term rental....or stay with family or friends.

I think it would be better just to stay on good terms and let him know you will contact him when you are ready to sell.

@Joshua MiddletonI am very familiar with that street, good friend used to rent Long term on it for about 7 years.  

Passive income is certainly the name of the game - building a real estate portfolio and creating generational wealth are key ingredients to long term holistic financial health and success.There are fantastic real estate investment opportunities in various markets, particularly in the Midwest and Southeast of the country.