Thank you all for the valuable input. This is what I have concluded based on all of the advice:
I am going to purchase three Penguin II 15k with Heat Pumps and two MicroAir thermostats (I already have two on the current AC units - I will make a heck of a deal). I am going to set the dip switches to match what I currently have, which is three zones. I should not have to replace the current wiring - plug and play. Also, I should not have to mess with the intake vents or the distribution box on the inside, just use what I already have. On my coach, there is a beautiful wood trim ring around the vent in the front and the one in the back with a much less beautiful distribution box in the center.
It should be a relatively simple install with no cutting, welding, wiring, etc. - Correct?
Thanks again.