You use the cap rate to determine a fair price to offer for the property.It's impossible to say whether this is a good deal for you or not without knowing all of the numbers as well as what your goals are.  

I personally would like to keep the property, however admittedly without good management, it seems almost impossible. 

It was definitely a challenge especially since it is impossible to get anybody on the phone and emails go unanswered for days.

It is impossible to give you answers without knowing more detail.

Not impossible but not easy neither especially for someone that's starting out..As @Jiri B. mentioned $15K  for a downpayment and rehab cost seems pretty low.

So it would be difficult or near impossible to get someone to sell and assign a tax lien.

As Wayne B. said, it is almost impossible to make the math work in California unless you find a total dump in foreclosure or go really out into the most rural areas.

How much from signage, thats impossible to say.

Lastly in the whatever its worth file.. we never market a home for sale with a tenant in it.. unless your in high dollar areas like bay area or la or north chicago or DC boston NYC  type placeswith grade A tenants .. its virtually impossible to sell the home with a tenant in there. 

Your math of $76K profit for 17 hours work that makes it sound like it is repeatable over and over would be amazing but sounds impossible.