I know you don't want to deal with tenants and their problems, so why not either:A - Buy a NNN property where you don't have those problems, but still have cash flow,...orB - Take your $500k, and partner up with another investor where they deal with the tenants.

How did you find this deal and how did you negotiate it?

So far, this approach has saved my team so much time when sourcing on market deals.

Back then looking at more deals would eventually get you a "quality" deal, today it will get you a deal in the hood.

Without involving a traditional lender, what kind of deal structures should we consider?

The Menu, DEALS!

To only invest $5k into the deal with those returns is fantastic. 

Do you have tips for structuring short-term leases that protect me as a landlord while accommodating their needs?

It takes a long time to find an off market deal.

To save those costs, you might want to stick to some year build and older, for example, if you cannot do inspections on the properties that you are buying due to off-market deals or something else that is hindering you (all sellers I buy from do not want anyone in the home till we close).