Great post, Mark.
I think along similar lines - The machines are often neglected and poorly maintained during their route days, and sometimes ever further neglected once privately owned. I tend to target the VERY neglected machines as they deserve to be treated better and the results can often be VERY satisfying post restoration.
My "signature" restoration was a Gottlieb Jacks Open. Around 200 hours and fully rebuilt. I coined the phrase "Nearly In Box" as it was a close to Original condition as it was ever going to get.
