How do you get accurate numbers to determine ROI? 

I know the portfolio isn't huge, but it's somewhat diverse.

Second thing would be to work with a contractor, this is great stuff to do since you know building a house, building material costs, and knowledge of right and wrong what to do. 

You want to talk to friends and family on this, I don't know anyone who would see this on the Internet and be like, yeah, this sounds like exactly what I am looking to do with my money.

Before you commit money and time, look into:  How long are houses currently "On Market", (Is inventory growing or getting more scarce) and into prices.  

Ask how many units they manage and how much experience they have.

A PMC is like insurance - how long would you choose for your family to live without medical insurance?

Again its all in how much meat there is on a deal.

Your biggest challanges:1) Figuring out how to advertise on Zillow2) Handling all the calls3) Scheduling showings - and getting stood up4) Finding a rental application to use - you can use Zillow's or easily Google for one.5) Figuring out how to screen applicants ***** This is IMPORTANT!

I know there is surety bond process and there a a few companies that appear to offer a service (Like Rhino)Furnished Finder has a new feature called Worry Free Waivers but when I tried  to better understand their process, it was clear they have not done a good job of vetting this out.