According to him, the park has never kicked anyone out for purely age of trailer and no real intentions of doing so.

If it's purely a deposit dispute, and not a specific performance claim, you should be able to continue marketing and selling the property to someone else.

If you refinance the property and get all of your initial purchase plus renovation costs (possibly more) and are still making money, that money is pure profit and you can do it again but possibly better.As you compound that monthly cash flow, it decreases the costs of materials and labor for the next BRRR/Build/Flip and you're making even more money on the refi/sale.The idea is to expand your money supply through other people's ability to pay rent and pay for the financing.  

From a pure investment standpoint I know it's lower than what the market would demand. 

From a purely financial perspective your cheapest money comes from your home.

This was my first purely investment property and there were some hard lessons learned, but despite the challenges, this property has provided me consistent cash flow.

This will be purely for rent and not own occupied as we want to live in Shaker.

We have been able to turn pure rentals 20% down and 0% personal turned rentals into a great strategy that is building a passive income stream for us.

For a more pure IRR calc, you'd need to take the 2008 purchase at $1.75, add another $20k invested to remodel a bathroom in 2013, add another $750k investment in 2016 and then the sale at $3.9M in late 2020. 

What makes it difficult is that it's not purely an investment property - I love the neighborhood and plan on living in the place for some years...Any advice would be welcome!