It all in the eye of the beholder, or beer holder......judging by what some people think is a good idea, no matter what era the subject. You wouldn't need to go crazy with swapped out lighs, adding un-needed lights, adding skirts (which frankly haven't looked good or right on new vehicles since the late 60's-mid 70's), painting over or adding extra, tack on chrome, etc.
For example:
First gen Chrysler LHS, mild drop if not a set of air bags, shave most of the badging and door handles, swap in the chromed New Yorker grill, then find a complimentary wheels of a reasonable size (maybe even stock sized!) That simple cleaning up of the car could make it a nice cruiser.
Same with the Buick Lucerne, not a whole lot of work, basically the same as outlined for the LHS and would likely result in the same, clean cruiser look.