Painting travel trailer white to reduce heat in summer?

My 1st 5th wheel rv trailer was a 26' new 1984 Aljo by Skyline which had the typical mill finish aluminum roof. Man was it ever hot.
I used 2 coats KoolSeal white Elastomeric roof coating. It made the trailer much cooler when we had to camp in direct sun and 110 degree heat here in OK.

But being a camper with 2" thick walls and probably R7 insulating value all around it was still hot.

That was years ago and not being youngsters we don't camp in that kind of heat anymore.