...came home to find that the guy who plans to paint the place took out all the doors!!

Just from looking in the windows I seen all original trim,doors, floors,baseboards, mantals & light fixtures.

Knocking on doors can work.

What if I'm to leave a simple yellow letter on someones front door?

But then again retirement is still many, many years off for me, so I'm thinking my best strategy may be to bet on Southern California appreciation for the long haul...I don't plan to quit my job any time soon, and I'd take 1% greater average year-over-year appreciation over the next 30 years over an extra couple hundred bucks monthly cash flow per door by picking up property in Cleveland or Indianapolis...decisions, decisions...Let's say you were in your 20s and could do it over again.  

You can do a little work yourself and get a list of properties that fit your specs that are absentee owners from listsource and then either knock doors or conduct a direct mail campaign. 

What is your objective for door knocking? 

Of course, it has to be in your brand new-car, and you have to pay the gas and probably get this investor to lunch, after this you may have to write 30 offers,  all way below asking price, and if you are lucky enough, you put one under contract, then you have to go with your buyer to inspections and very likely you have to open the door to 2 or 3 contractors so they can start doing an estimate.

Direct mail, door knocking, cold calling, craigslist ads, word of mouth, instagram, facebook, twitter.

If you struggle to make connections and people are clearing out, wait around for an opportunity to speak with the organizer who will be the last one out the door.