It feels like a slow rate of growth but it is working for now. 

The difference is that your duplex, you can just hold for 30 years on that nice fixed rate mortgage if the market is soft next year.

Typically the rates change depending on if you are occupying the property or not.The reason most people talk about house hacking is because of the benefit of lowering your expenses. 

We would have trouble cash flowing if we were to do a cash out refinance with the current interest rates.

Almost any $65k property in a Midwest city is going to be Class D or need $20k+ in rehab.Class D means you'll only get the worst tenants, who have a high rate of eviction for nonpayment AND they trash the place on their way out.You MAY get lucky and get a S8 tenant for your Class D rental, but most of them will want to live in a better neighborhood.

I am assuming something similar would happen to Americas credit rating? 

Unless rates lower it may be status quo.

Good question, I don't think I'll get the rent I need for the PITI on the place at a long term rate.

Quick increases in value are hard to come by, unless the area gets really hot and interest rates drop a lot, creating a frenzy.

The rents are high enough so they can cashflow, even with the 7%-8% rates we are currently seeing.