In Southern Cal you can look zip code to zip code and put an average PSF $ on properties.

Contract law says that you would have to honor any lease that is in place, however, in this case the fact that it is a SEC 8 tenant will benefit you because SEC requires a new lease be signed when there is a new Payee (owner or property manager).  

I won a Default Judgement for $18K plus interest and the 5 Year Statute should have given me the property, but, the Judge did not want to honor that.

All entry doors (in Calif) must be solid core, not like hollow core closet doors.Depending upon the floor plan, you may also need a fire-door rating -- just ask the City Codes department.

Check fair housing codes and your state landlord tenant regulations.

Instead of driving all over town looking for distressed properties  why don't  you just look at the housing code violations?

What has work for me in the past is just picking a few target zip codes pulling how many cash sales are in that area then deciding if It would be a good area for me to farm numbers and start calling around to gauge motivation!

USPS site under lookup zip codes. 

Having someone in the house doesn't prevent you from selling it, it just means the new owner will have to honor the lease and you would have to give them whatever payments remained.

You may be able to avoid this by placing them out on Friday evenings and picking them back up on Sunday evenings, as code enforcement officials will likely be off duty for the weekend.