You don’t need necessarily need to build credit.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Note: I'll caveat: I believe that other factors should be considered when analyzing the market as well (i.e. economic growth/stability, low crime rate, affordability, etc.)

Ours tenants mostly pay online, 93%, by ACH, debit, and credit card.

I think I would be more worried about the credit than I am about the DUI.

The return on equity is probably very low considering they are paid off so maybe explore refinancing or selling the lowest performing one(s) or your biggest headaches to reinvest in more lucrative deals.I noticed you also used a metric of number of rentals to attain your goal rather than $$$/month.

Quote from @NA Hirsch: What service do you recommend for doing a soft pull on a potential borrower's credit?

If low wet ground check with people moving dirt for free fill dirt.

Their character, their payment record, how well they take care of you property, etc all these things are for you to discover with your tenants and build trust between each other. 2. when it comes to screening, you must check their credit, their paystubs, their employer and landlord references, their criminal background, I also get a copy of everyone's photo ID.3.

Is there a way I can take on the current mortgage payments (at the low rate) and get a new mortgage to make up the difference between the existing mortgage and the current value?