The 4 financed properties are worth - $606,040 - a $50,040 gain.During that time, your tenants paid down your mortgage with each of their rent payments as well, so you have an increase in equity on the financed properties as well.Then there are the tax write-offs.  

I have about 180k in equity on the single-family, but am wondering how much debt I really want/need to take on.

Paying off a $100,000 note doesn't mean you have $100,000 in equity...

I already have over 4 mil in equity.

*Once I did pull out the $25,000 to $65,000 in equity would you suggest I just do 20% down?

When you are doing a direct exchange (you and I exchange properties with each other), you only have a totally tax deferred exchange if you are trading equal or up in equity AND debt.In the delayed exchange that you are proposing, you engage the service of a qualified intermediary to sell your relinquished property to a third party, then acquire your replacement property from a fourth party.

From experience, I've learned I typically don't mess with a preforeclosure unless it has at least $40k in equity.

I currently have $55k in equity in my main property.

In other words, it doesn't prevent a borrower from making a fuss and requiring a formal process with 8% or 10% or 15% in equity.

Bummer; I was hoping for a tax-free exchange and hoped trading up in equity and debt would be enough to ensure this.Now I'm reading that some accountants treat these items not as an expense but as non-recourse debt that has been assumed by the buyer of the property, and therefore can be netted against debt I assumed with the replacement property.