The problem with such an old car is that you can't just run into Autozone and find a new gasket or bushing or other parts.
This isnt exactly true. Its highly dependant on the M/M.
For example, I can walk into my local O'reilly (AutoZones in my area have consistently got the wrong part every time so I avoid them now) and get pretty much any mechanical part I need for my 1968 Ford Galaxie 500. And if not that day, then by the next day. This is because Ford shared a lot of mechanical parts between many models for many years, so things like drums and shoes, starters, wheel cylinders, engine parts including gaskets, suspension bushings, etc. are all pretty easy to find and buy. They're also incredibly cheap. I bought a wheel cylinder for $15 USD, and a brand new starter only set me back $45 USD. This is in California, which is pretty notorious for high cost items. For any part that my local stores don't have, RockAuto is guaranteed to have it. They even happened to have the rare factory style air-conditioning vacuum valve tree for directing coolant into the heater core I need to get heat in my car for just $20 USD (which I promptly bought 2).
For non-mechanical parts like interior trim, mirrors, etc, that stuff is all really hard to find. I have had to custom order some of these parts myself, especially since the 1968 Galaxie was its own model, the 1967 and 1969 models had different designs that use incompatible parts.
By comparison to modern cars, I found myself getting parts actually faster than the modern cars I repair for a living. Seems like every new car part is SOP these days, 1 to 2 weeks out.