When factoring in the Equity Accrued; is this basically the equivalent of whatever portion was paid down from the principal of the loan?  

This is the time where you will see a short sale pop up, and or the property is empty and the bank starts to maintain the property so it doesn't accrue and municipal fines, or damage.

Depending on your exit strategy, there can be many ways to obtain wealth…including the 15-year mortgage strategy that builds up equity quicker with less interest accruing over time, and being able to speed up the process of having higher rent returns as well by paying down the principal quicker.

The TSP will declare a taxable distribution on the entire unpaid balance of your loan plus accrued interest:If you fail to repay your loan(s) in accordance with your Loan Agreement.If you miss a loan payment and you do not make it up within the specified time period.If you do not repay your loan when you separate from Federal service.

And your heirs get the step up in basis so any tax and accrued depreciation disappear at your death. 

Your returns aren't going to set the world on fire but it's guaranteed not to lose principle and if you cash a cd in early,  you'll only loose the accrued interest.

The problem is that there is a substantial multi-year real estate tax bill that the owner has accrued which he could never hope to pay off.  

I was looking to get out of my 9-5 corporate job, so getting a license has become my primary source of income, on top of rental properties I've accrued.

Typically the moment you get the money interest starts to accrue.

But the small incremental cash flow you'd get from no mortgage payments would have to accrue year after year until you can buy another cash following property.