We typically pay somewhere in the range of $3500 for a new, basic furnance, including install, if there are no other modifications to the system required.  

It's a range and depends on the property type, location, end condition and rental strategy. 

Or, you could ask for a rate quote based on a range of credit scores and you can figure out what they'd charge you on your own.

There are several articles that do an exceptional job of explaining who, what, where, why and how tax payers qualify for the ‘STR Loophole’ listed here:The Short Term Rental Tax Loop Hole: A Game Changer for W-2 Wage EarnersThe Short Term Tax Rental Loop Hole: What Investors need to know The implications on the Oregon and California Coastal STR market is a strengthening buyer pool for luxury rentals in the $750-1.5M+ range.

After 5 years, my wife and I decided to make a change and moved to Nashville TN where I work as a project manager on projects ranging from several million on up to around 300 million.

These range low 500s to the mid 600s.

Quote from @Jaycee Greene: Assuming you pay asking price, I'd estimate the down payment for something like that using a hard money loan (HML) would be around 40% of the purchase price and your monthly payment would be $2,600 with an interest rate in the low 7% range (probably need a 700+ credit score to get that).

For similar reasons you mentioned with access to both I70 and I90 pretty easily as well as being in range for the eastern sea board makes it a logistics hub.  

An idle brain/body just begins to get worse if you stop using them.

Do you have an idea of the type of property you want to buy and a price range?