If you could match it, the red would match your jeep and look nice.
But, according to information posted elsewhere on this forum, the white would stay cooler.
Plus, red is known to oxidize easily. The red on the jeep and the red on the trailer my react differently when it comes to that. Thus, they might change to different shades or coloring down the road....
Alternative: Why not paint it white
and red?! That way, the part that is closest to the sun (the top) could reflect heat and any red accents would not have to match your jeep exactly to look good. Of course, this challenges you to put your thinking cap on and come up with a design that you'd like.....