jcpainter,
The internal fan doesn't help it cool, but it will keep all the frig at a more even temp.
I prefer the $15 dollar battery operated one. 2 D cells last a month and it takes up only small amount of room and you can move it around on the shelves.
I bought the one that clips onto the evaporator fins but it was a pain to use. Things in the frig would bump it and knock it off or hit the fan and stop it from turning.
Adding an external fan to pull the heat out of the condenser vent does sometimes help the unit get to the temp you want.
If your frig is on a slide out you should already have the external vent fan as it doesn't vent through the roof.
If your frig works better on electric than on propane you may need to clean the burner assembly.