Ourcurrent approach involves identifying possible contact information for thelisted owners and calling multiple numbers, but this process is time-consumingand yields limited results.

It would be nice if you had a contact who was an actual mason not a marketer.  1930's construction is rare so maybe they cut some corners it was a global depression.  

Contact the utility provider and get a historical average based on the last year of use.

Hey Dominic, I have some good contacts to help you out.

A contact of mine has been thriving with STR investments in suburban Chicago, targeting guests visiting for conferences.

We deny showing all the time because people won't share their contact info.

Happy to share some contacts with you if this is something that interests you. 

And if you have been keeping people's contact info, you could pass that on to him as well so he can send out a change of ownership letter.it's just going to depend on the specific property and the specific buyer that wanders along.

But it sounds like we'll have to swallow our pride and take your advice and contact a few real estate agencies.

If you're willing to be more active, purchase a property or two in an area you personally know well and have key contacts (handypeople, contractor, lender, etc.).