The Airbnb calculator estimated higher returns than in most places I've looked, as did local property managers.

Find a few GC's local to the market you're interested in. 

Separately — and this is a more minor gripe — it was complicating my tax situation to pay state and local income taxes in a place I didn't live anymore.I pitched to my parents that I would sell the place and roll it over into a comparable property closer to where I live.

@Roseann Koefoed,As long as you have legitimate self-employment or an active business, you will be able to establish a self-directed Solo 401k plan.

Currently I've been working on trying to get my active income up, because I have no other source of income than the duplex cashflow ($1100/mo).

I would look into local and state apartment associations.

Bank Five Nine just launched a new DSCR product last week, but there are several local banks in Milwaukee that are great to work with.Have you been to Milwaukee and have you seen this property in person?

Trick that I am learning:  work on overcoming your fears, pull leads, get on the phone, talk to sellers, local brokers, other investors, other RE partners, etc. 

I'd start locally doing BRRRs, use your experience.

This team should include professionals like agents, lenders, contractors, and property managers.Lastly, connect with other investors and attend local REI networking groups and meetups.