St. Louis investing/househacking

[Jacob Rey]

Hi everyone!

I am new to investing and am trying to find a good duplex for my first househack/foray into real estate investing. Any thoughts, advice, or area specific insights would be MUCH appreciated. 
I keep doing the math, and it’s hard to not come out on top if I were to sell after 10-15 years. 
I am unsure of WHAT numbers to crunch aside from taxes, rent, maintenance, accounting for vacancy, unsure about cap rates, etc. However, if I plug numbers into a rental calculator it all seems good.
I’ve been reading and doing calculations, but feel like I have to be missing something. 
thank you for your time!!