Protecting surface that has small surface rust already?

Cheap and fast.
Spray affected area with clear from a spray bomb. hit it a couple times. All you need to do in effect is seal the area from more oxidation(air and water). used this method for a couple years now on my projects that are outside.

Vinyl top: use a lot of cheap Lacquer thinner. you can buy a 5 gallon can for 30 bucks at discount autobody supply stores. works good for cleaning all sorts of thing on cars.... check small areas at first to see if it will damage the material(many plastics dissolve.) Spead it on in a small area at a time using cotton rags to soak up the goo. Throw everything into a metal can out side your garage, and use ventilation! (it's a cheap but painful headache high....