I personally like Indianapolis and Kansas City for the combination of cash flow but also strong demographic trends such as population growth, job growth and modern/diverse economies.

Zanesville is pretty diverse.

If it's just because you know contacts, be sure that is enough.Contacts won't make purchase prices lower, unemployment better, job diversity higher or rent growth numbers to increase.

I think I could build a successful portfolio there, but not one that's going generate the level of income that I want long term, so I'm thinking to start there and diversity into another more expensive market later. 

I have a diverse 28 door portfolio (everything from luxury STR's to low income LTR's), and they are all affected (although we will see what happens when rent is due on the 1st).

You want a market with JOBS, population growth, and diverse employment.

Employment is incredibly diverse with multiple Fortune 500 companies, and it's got one of the nation's lowest vacancy rates, in addition to a recognized shortage of affordable housing & strong city incentives for section 8 rentals.

After i've done some research looking at the population growth, job diversity, unemployment rate, etc...

And, it will be a forever process; real estate is so diverse and always changing that if anyone tells you that know everything about real estate, you should thank them for the warning and bolt!

.; foundation/structural settling, improper water diversion systems creating rot, etc.