White is easy to clean - wash and drive as white doesn't show water spots. White is easy color to see for other drivers according to insurance companies so it's popular with big trucks and semis. What is a neutral color and goes with any trailer. Pick the trailer color you like 1st. Chances are, you will have your new RV longer than you will have your truck.
My 2006 truck is 2 tone like Felicia & Jeff's new one. If you go back to 2006, I found pictures of 5th wheel RV's that were a simular color combo theme to these King Ranch trucks. Anyway, a pic of a white truck wtih cream/brown Columbus.