There is no specific distance requirement from your primary residence but it must pass the smell test. 15% down is the minimum required down payment for an investment property.

Stress test it with various interest rate scenarios: just to use round #s if you pay down 75K in five years  what does your new loan look like at 4%/6%/8% etc.

Also, make sure to square away the utilities, find out if you owe taxes for 2021, as mentioned above get the data on the tenants.

My auditor said could not combine time spent on my multiple rental properties to make the 750 hrs criteria, rather that much time had to be on a single property.So if you want to test the rules and think it is worth it have a good time. 

Since I plan on doing this for at least the next 6 months, I want to be as organized as I can so I can keep track of leads, contacts, and data.

That was 7 years ago so don't have any recent data on them 

But what are the limits and tests I have to pass?  

Find the data at the following link:  Median Price Multifamily Aurora Elgin

I see this in the data and also in my business: we work with a lot of relocation clients and the reasons (for moving to Milwaukee) are usually cost of living, followed by smoke (from the fires), water (droughts in the SW) or floods.

I haven't take the time to look at the real data on what's going on with the rental market in Chicago but our system has blown up with inquiries.