Especially seeing that the primary airport is too small and geographically constrained.  

Our primary residents also has some equity, I have a HELOC with $166,000 available funds.

I wouldn't own so much real estate if I didn't make RE my primary business.

I'm not sure that the property being perfect for your investment criteria makes it unique enough to warrant a judge forcing the sale, especially considering that it was not listed for sale to begin with and that you're going to be using it for an investment property not a primary residence.

I have found that I get more appreciation on the single family house because I can sell it to an investor or as a primary residence.

In some cases, after running the numbers, I’ve even faced potential negative returns, causing me to miss out on promising deals here in South Florida.That brings me to my question: I currently own two homes—one is my primary residence, and the other is a rental property.

For the $525K property, with the low mortgage rate(you will probably never get a such low rate), it might make sense to hold onto it for now, especially if you can still sell it as a primary residence within the next three years and avoid capital gains taxes.

Would the buyers/borrowers be purchasing with the intent of putting a mobile home on the property and making it their primary residence?

If the interest rate are close, then you should pay off the primary. 

The two existing LTR units (on my family’s property) were built 5–8 years ago at a cost of about $80,000 per unit, so I’m estimating a 20% increase in costs for the new builds.My plan is to use the equity in the land as the down payment for the construction loan, which I expect will make closing costs the primary upfront expense.