Best option is not to leave the Escort anywhere where it is exposed and where it can attract the wrong type of attraction.
My Escort is my daily and is never far away from me.
If we need to go out and park in a public place we aways take the Mrs late model car.
Most keys will open a 30 plus year old worn lock without damage.
 
 

Just purchased http://www.amazon.com/gp/...oh_details_o00_s00_i03 for about $40 to the door, should be a fun install, my Dad has a 2 door central locking kit which I might pinch for this too... Ill let you know how I go with it, let me know if anyone has advice for installing the central locking kit (ive installed a few before but not on the Escort)...

The alarm is definately worth it.. someone smashed my window and the alarm went off, stopped them getting any further. Mine is remote and tied into the immobiliser and central locking. I think its important to have a visible flashing LED.
To really reduce the chance of theft as everyone is saying put on a steering lock as a visual deterant, and take something out (rotor button, ECU, ignition module, fuse etc) that will stop it starting / running.
I had an EF falcon, and I almost never locked it (central locking was faulty). I always left change in the cup holder (visible from outside). in 2 years, the change never got taken. Really suprised me...
 
Andrew