When I looked into restoring my wife’s piano there was hardly any resources to turn to for guidance. Google produced just one person within a 100 mile radius who seemed even remotely qualified. When I contacted him he basically let me know up front that it would be unbelievably expensive and likely not produce the results I was hoping for due to its age and years of neglect.
Apparently many of these old uprights have iron frames that become brittle with age (another reason why they are so damn heavy). Wooden sound boards are even worse if they haven’t been maintained over the years. You can’t just go in there with a wrench and start tightening things. Essentially you have to re-build the sound board entirely with new parts, re-string, tune and balance the whole thing. It may look great on the outside but it’s the innards that makes the difference. Unless it’s a family heirloom or truly a classic model, you will never recoup that investment.