For appraisal, highly suggest the C&V section at:
Classic and Vintage Bicycles: Whats it Worth? Appraisals and Inquiries - Bike Forums

Also, there's a pretty decent frameset only in the C&V for sale section. Some issues but something for you to compare with.

As for this particular bike, I highly doubt it only had 20 miles on it. The larger issue is the non-factory fork and question why it was replaced. Regardless its a neat bike and with a thorough service, sorting out, cleaning, could be just right for someone. Good luck!