We used the cash for keys approach and got him out but it could have been drawn out and unexpected damages which thankfully we avoided.  

What is the extent of the damage and can you include any pictures?

The worst one was evicted and left $20,000 in damages and unpaid rent.

Payment would be $824 plus taxes and insurance of $350. like 1174If you don't get hazard insurance and ANY damages happen, you lose.

I have concerns such as what if the tenant just abandons the house without informing me and leaves or damages the house.3.

The C class and lower are too unpredictable and you will start to blame your vendors for rents not being paid, damage to units, and other issues that arise.If you are investing out of state take a low risk approach. 

Total damage $720-The heater didn't work because my thermostat wasn't compatible with my HVAC unit.

Last thing, forget the classical causation for appreciation and think about this, if you can buy several properties in one community/neighborhood and restore them and place families in them, by creating the right kind of density in the neighborhood, the value right around your homes will rise. 

At first I wanted to be moving on from the nightmare of horrendous tenants' damage.

I need to get a landlord lawyer for me to recoup two years of lost rent and damages for the unit.