I have had from dark colored to light colored motorhomes. When I purchased my current coach, which as you can see in my avatar has a light colored base, someone commented that the color would really help in cooling it. At the time, I tucked that back into my head to do a test someday. My darkest colored coach was a bear to cool when it was over 90 degrees. This one, not too bad.
Yesterday, when the ambient temperature was near 90 degrees and the sun was beating on the side of the unit I got reminded to do the temp tests when I reached for the door handle surrounded by a black bezel and was surprised just how hot it was! I pulled out the heat gun and did some tests. Here's the results, for what they are worth.
My coach has a very dark maroon color in places. One of those places is near the door handle. I couldn't believe this temp!
Next, I tested on a copper color, which I considered kind of a medium color:
Finally, I tested on the base color, which is light:
Almost 40 degrees F of difference dark to light. And no wonder my fingers were scorched when I touched the black door handle! Clearly, your color choice (as well as other factors, of course) will have a significant difference on how hard your AC's have to work in hot weather to cool your coach. Another point is that on the shaded side of the rig, there was still a temperature difference between dark and light colors even after hours of being shaded! It was only a few degrees, but it had been quite a while with no direct sunlight on it.
As long as I was at it I decided to see just what the tire covers did. I have light grey tire covers. Here is the temp on the tire cover:
Here is the temp under the cover on the tire itself:
Looking at the avg temps (I was holding on the target for about 5 seconds) it's almost a 35 degree difference. So not only is the tire cover protecting from harmful UV, it's also keeping the tire substantially cooler. And imagine, based on the color differences above, what a black tire surface temp might have been!
So for what it's worth, these may be things to keep in mind as you go about selecting colors for the coach and various other accessories, especially if you will be using them in hot sunny conditions. It made me wish I would have gotten white tire covers instead of grey and happy that my base coach color is light!