What is the best legal structure to assume his existing land contract while either concurrently paying him or writing up a 2nd land contract to the seller past the 4 years on the current land contract?

You definitely do not need coaching on anything right now because you don't want to pay someone to make your decision for you.

I paid cash, but borrowed 30k from a family member to cover some extra costs and renovation, the HOA fee is $135, and I pay my family member $500 a month until the 30k is paid off.

But I have used the MyFico site to improve my credit by myself, largely by paying attention to the utilization thresholds. 

When we purchased our third home, we did not qualify for the rate as a second home and had to pay the rate as an investment.

But then, as short-term rentals became ever more popular, Americans tourists started thinking wait a second "We're paying so much for staying for a week at that short-term rental.

These are the only units that currently do not pay utilities, which amounts to about $250 per month per unit.

I ended up with the goal of living in the area paying less than what I would pay for rent ($1700) while building equity on a property.

So what exactly did we pay for?

How much is he paying you monthly to use your land?