I'd suggest using the calculators here on the site.

@Daniel Winsor Just make sure the language regarding the roof repair being tied to your required performance are Clear, not vague.

@Mindi Rosser & @Greg GerkenAs someone who does this work for a living, I can assure you, you do not want to get in the weeds with this stuff.Some investors spend way too much time getting the site up and running.

I will not be living there, so house hacking is a grey area (essentially I would be lying about living on site if I went that direction).

Additionally, every property is unique with different methods and terms of financing, performance, tax consequences, etc...

You may not personally benefit such as by drawing income from the rental personally, nor may you inject value into the IRA through the provision of goods or services such as performing work on the property.Basically, you get to be a fund manager and deploy your retirement savings into an asset class you know and understand with these vehicles. 

Start studying as much information as you can about real estate investing on sites like BP, YouTube videos, etc. 

I checked the Better Business Bureau for complaints, I checked the NJ State Attorney General consumer division to ensure he was licensed, I checked every reference he gave by visiting sites and speaking with the homeowners.

Here are a few methods that I know of to find these potential deals:- Go to a site and find apartments that have vacant units.

Make sure they are reliable and will perform the task you want them to perform.