Update on the 2017 Colorado while towing

Hi everyone, Hope that everyone is staying safe and virus free.
We just recently purchased a 2019 Dutchman/Coleman 1705RB camper.
It's 22 feet long 10'5" tall and 8' wide and sets pretty high " lots of ground clearance".
It weighs 4760 lbs loaded with full fresh water tank 40+ gallons, it has a single 4400 lb axle with 8 ply tires.
Truck & trailer G.V.C.W. of 12,700 lbs.
Weight on trailer axle loaded is 4,260 lbs. Tongue weight is 500 lbs.
I'm running a weight distribution hitch with an older style Reese dual cam anti sway system.
This trailer is a parachute compared to the low profile Chalet hard top pop up camper that we had previously.
It weighed about 2,200 lbs loaded. Truck was loaded with about 900 lbs in the bed not counting the two of us and two small dogs.
We averaged 25 mpg towing that up to West Virginia and back to Florida last year via route 81 in the hills and running speed limits when traffic allowed.
Towing this new camper about 200 miles in the rolling hills of Florida, and yes we have some hills but not like route 81 thru Virginia obviously.
We were running 65 to 70 mph on the highway portion and then some towns and traffic lights "of which I think we hit everyone Red" and most were at the bottom of a hill, why is that? LOL
We average 15.2 mpg towing this trailer. Do to the profile it has a lot more drag.
The truck pulled it with little or no effort, I was very surprised at how much power this Colorado puts out.
It had no problem starting, stopping or pulling hills at highway speeds or otherwise.
It was 94 degrees out and we did notice that my Trans temp got up to 230 degrees in some of the stop and go traffic. But most of the trip it stayed at 220 or even 215 degrees.
They claim that is normal and won't hurt it. I still may look into putting an auxiliary trans cooler on it though. If anyone has any experience on a Colorado Duramax truck with an external trans cooler, please chime in.
The trans felt fine and no funny shifts or otherwise.
Of course you can't pull the dip stick and look at or smell the fluid because it doesn't have one!
The exhaust brake worked extremely well and the integrated trailer brake controller worked well just as it did on the last trailer.
I have had the towing package with integrated brake controller on some of our 3500 Duramax Crew cabs and really liked the way they worked.
Truck was very quiet pulling just like the big one's are.
Everyone take care and stay safe.