It pays for the water, sewer, taxes, and provides us with a small cash flow distribution each year.

OR Do I hack with a HELOC or Cash out Refinance and optimize the revenue on the property ?  

It is beautiful out there but are people able to cash flow their existing STR. 

Granted, the current value gets you to your target cash-out number of $125,000 which is another option.

I also put in two properties that I own, one has 18 years left on a 20yr fixed and the other has been paid off in cash.

So here is a partial list of people who might be more inclined to listen to your offer of a cash discount, or some type of vendor financing:Financially Distressed HomeownersThese are people who may be facing financial hardships such as foreclosure or debt.

Also, I would like to buy it cash to get a better deal out of it and not have to pay for any interest or loan fees.

Cash flow is great if you can get it, but it's the icing, not the cake.Consider that Denver has averaged 6% year-over-year appreciation for more than 40 years.

I am considering purchasing a investment property to get some monthly cash flow from rent.

With an assumed loan providing a lower interest rate and accelerated amortization, the income generated from house hacking can be leveraged to pay down the mortgage principal even faster, or the extra cash could be saved to be used towards your next down payment!