How much readily available cash needed to safely expand?

[Maxim Lorenz]

I am Active Duty Officer and currently own a home in Texas with 85k left on loan (100k originally borrowed at 15 years conventional) on property that is around 300k at 4.25%. The tenants are leaving end of August and I will rerent at around $1900/mo.

I am closing on main property in Colorado for $470k at 2.5% VA with no money down (the rate was much better than conventional loan) and at 2.5% the general consensus was to borrow as much as possible.

I am looking to buy another property for Airbnb either in CO or TX. I have about 100k readily available cash (TSP, IRAs not included), but fear that if I use 100k (or a part of it) as down payment on another property I will not have enough cash buffer in case on emergency in the event of vacancy, repairs, etc. May be worst case cash out refinance property in TX?

TX property is self-managed. CO main property employer pays ~90% of mortgage. If all goes well, I'll retire in 4 years to a pension of ~5-6k/mo and should not have any problems securing well paid job due to nature of my work. However, that's then and there are too many what-ifs so I rather play it safer-ish. What's your take? Thanks.