You could get a crankset of the same vintage as your current one ... ie, NOT 8-9-10 speed crank.
That is the simplest solution and eliminates all the guessing about various compatibility options.

I have not tried a new narrow crank on an older drivetrain, so not sure if the old chain will work. If you go with a narrow chain too, I guess it would work with your freewheel. However, if your freewheel is old and worn, the chain may skip, so you'll need a new freewheel too.

Edit: Could be a cassette as Jeff pointed out below.