Scale quickly, BUY more LOL, not sure what else to say, 

Your price point doesn't help either, 300k is not a lot in these markets and at that price point you will be fighting with other locals buying full time houses.

We are looking to buy our first short-term rental investment property, which is 3 hours away.

Ask the seller to carry a note, but I'd buy a SFH instead of a duplex, especially if the duplex needs remodeling!

Have you considered offering buyer incentives like buying their rate down?

Here is my situation:- I'm a W2 employee that earns north of $500k a year- My wife is a stay-at-home-spouse- I'm looking to buy ~ $1,000,000 in STR Real Estate by the end of the year (as an investment and to offset my tax bill)I'm fairly well versed in the rules surrounding using STR to offset active income.

In my head I'd want to buy a property cash or creative terms with a private money partner for the home and maybe a 2nd partner for the furnishing and start-up funding.

DSCR would be your best bet but again 25% down and a DSCR of 1.25% minimum.Do yourself a favor and do not let just any Lender/loan officer pull your credit just so they can take an application and have a possible deal.

Investment Info:Small multi-family (2-4 units) buy & hold investment.

That said I am also reading that a higher price to rent ratio may indicate areas where it is more attractive to rent than to buy.