Garages are often cheaper to convert to ADUs than ground up construction, but not cheap enough to obtain a profit worth the effort.  

Their data and skip tracing isn't the best, but as you noted its cheap (you get what you pay for).

Columbus has some strong dynamics…cheap prices, 3 F500 companies, military, hospital, kayaking enthusiasts, Kia car plant.It has as many bad parts as good, so do your research, but I do believe if it is just about the investment, there’s some money to be made there

If you are convinced this is the guru you want to follow, pick up a cheap resale on amazon or ebay...read and study it cover to cover. 

  $560 is pretty cheap. 

Furthermore, what has been your results as far as Delivery %, Response %.

I agree with the need of a furnace.Most mountain cabins have hot tubs.Emergency generators aren't cheap, but great to have during a sustained power outage.I've thought a battery backup system might be a good compromise.

We use ours enough that they will waive their delivery fee once per tenant stay.

I know you don't want them using the box, but there's really no harm to you and it's only until a new tenant is placed, then USPS will change the locks.However, you could let the post office know the unit is vacant and ask them to stop delivery to that address until a new tenant is placed.

Cheap house with a decent profit How did you find this deal and how did you negotiate it?