Hey man. Don't really worry about vacuum on c10's. I can see by your profile that you live in Kansas City, which doesn't have heat/smog emission laws. So almost all of that you can pretty much delete.
The things that are important to have vacuum is your Vacuum Advance (IMG_5428 Vacuum on Distributor), Your choke pulloff (IMG_5428 Vacuum on Carb), and your cruise control (IMG_5432, the drum that has an arm that connects to the carb throttle). And the heater/AC Vacuum. You don't have to connect anything to your Canister cause those things, especially if it's old, get leaky.
Things you can plug is the EFE, and Manifold ports that aren't being used. There is also vacuum that comes from the back of the carb, but not on the carb In front of the distributor that connects to the intake manifold and is usually what people connect the brake booster and cruise control to. This is manifold vacuum and works exactly like the carburetor manifold vacuum does, it's just in a cleaner spot and gets it from the Intake directly.
The valves on your Thermostat (EFE TVS) and on your intake (EGR TVS) shouldn't be plugged unless you are leading them to sensors n stuff. If your aren't leading them, just leave them blowing. These aren't really necessary to connect but if you want to do it, it never hurts. EFE TVS releases heat from coolant, and EGR TVS releases heat from engine. EFE TVS should be hooked up to your temperature sensor and manifold vacuum through another hole. It should also be hooked up to your EFE. EGR TVS should be connected to your EGR bleed and Manifold vacuum through another hole. Then other holes on them should be plugged.