Originally Posted by Road Fan

I would approach that crankset with care. Cotter pin cranks can be tough to take apart, and to get back together correctly. Not that it won't benefit from help, but it can be done wrong.

As far as general disassembly and replacement, you should think in terms of internal cleaning and regreasing. Hubs and BB parts will not be easy to find except from donor bikes, and even there, these machines still are in demand. For example, if the races and cones from the front wheel are acceptable, re-use them. Replacing the whole hub is a big job, and getting a well-matched replacement wheel could also be a problem.

I recently saw a refurb 3-speed at a shop, where the brakes, same old steel calipers as you have, had been tweaked and tuned to the point where they felt as good as new single pivot brakes. Wholesale replacement should not be needed.

Test cleaners on painted areas where a problem would not be noticed, like on the inside of a fork blade.