My wife and I recently bought a 1964 Chevy panel truck. The previous owner had installed the engine and transmission from a 1990 Chevy Caprice. He had figured out how to make the manual shifter on the steering column work to shift the automatic transmission. Its a bit awkward because if you shift it incorrectly it locks up. The truck runs and has the original drive train. We would like to upgrade the drive train to be able drive it regularly so we're not looking to make it show quality. I'm not sure the best way to get started. I do know it would be nice to be able to shift the transmission without having to worry about it locking up. Eventually we would like to get rid of the carbureted engine. I have been told that the drive train from a 1988 pickup would bolt into our frame. I am looking for any advice on the best way to proceed.
You keep using the words "drive train" and "running gear". Let us know what you want, what you don't like other than the trans linkage which Jerry already said should be changed to Lokar or equivalent.
We don't know if you have a 700r4 or a 350 or what transmission. We don't know what a 88 "drive train" does for you. "Bolt on"? sort of, after a whole lot of work with equipment and skills. After rebuilding the 88 with equipment and skills.
Generally speaking, a 1964 Chevy truck has fairly modern axles, differential and etc. So hence the question "what are you trying to improve".
Chugiak seems to have few streets and is near a highway. I would imagine slippery conditions many parts of the year. So I would imagine high speeds are not important. But not sure what "driving experience" you want to experience. Leave the good old truck alone and drive carefully. These is a lot less to go wrong with a carb vs injection.
Disc brakes may be a good idea in wet environment, but no help in snow or ice. The "power" part is just easier to push the pedal.
I would concentrate on the heater, defrost (which is missing) and good tires

Not sure but seems you are asking about things you can do but are having someone else do them. Any kit made for your truck will work on your truck depending on what the goal is.
BTW: Nice panel.
BTW: It's not a 1964. If the hood is correct, it's a 1962 or 1963 Chevy with a GMC grill. The VIN may help.
Gauge cluster is custom aftermarket from what I see.