Kevin I think you have made the right choose!
I have used the little cube fan inside the fridge
for years - as Thomas indicated it really only moves air around but it helps! The instructions with my current one said it was best placed at the bottom of the fridge
. If you get one make sure you get the one with an on off switch - one of the ones doesnt have a switch and I could never remember to pull the batteries out of it when not in use. The one with on/off switch can last me a year of camping on one set of batteries.
The big thing to remember about the inside of the fridge
is - dont over fill it! If is over packed nothing will cool it down. Best to keep you none perishable items in a separate cooler. Also don't let the freezer compartment frost up. The more frost in the freezer area the poorer the fridge will run.
Two other things I have done that had a far bigger impact on better fridge performance were adding a small fan outside at the bottom of the fridge pointed upwards (leaving the bottom vent open a little bit) and wrapping the outside of the fridge in foil bubble wrap type insulation and resealing the area the fridge is enclosed - both inside the trailer and at the back. Scamp
had not done a great job of that - there were a few spots inside the cabinet area that were wide open.
Putting a wireless outdoor temperature sensor inside the fridge is another great item to have. Put the readout panel outside the fridge saves having to open the door to check how well the fridge is performing. Have found it often takes in really warm weather a good hour for the fridge to recover from having opened the door.