I have two thoughts.  1)  If you can convert your 401K to Self Directed IRA that may be an option to invest INSIDE your retirement account.   60K is much for buying a property but you could can lend it out to get 10%+ returns.  2)  Have you looked into a HELOC 2nd loan on you house? 

💪👊I'm an active duty AF, about to retire as well in the next few months, any advice on transitioning?

I will say, with furnished rentals, it takes time and money to fully furnish them with all the bells and whistles but it did allow me to get higher rents... only downside is, if you are out of state, it is not easy to manage remote unless you have a good property manager/company.I have personally started to transition out of STRs due to zoning/town regulations and have already unfurnished one of the apartments to turn it into a long rental for more stable residual income.

The Riviera Maya and Cancun area for example has has an 8 to 10% capital gain per year in the last 10 years, the politics are stable  and the country's international tourism is booming.

Make stable profit first, and then decide if you feel inclined to use part of your assets charitably.That's my two cents, at least.

I hope to retire in 9 years, so debt elimination or cash flow matching debt payments is fine by me.

Our ultimate end goal is to create passive income for retirement within 10 years.

I have a Associate Degree in a completely unrelated field.Seeing as how we are planning to make real estate the foundation of our day-to-day income stream and long-term "retirement" strategy, it feels as if making another change of profession is in the cards.

Plan is so that he can retire and him and my Mom can be financially secure on rental income while my sister and I manage the properties in the trust. 

Yes, I own rentals in my retirement account and also hundreds of my clients.