This post may be a little late. Those temps are too high, even for that environment. Id recommend blowing the radiator, charge air cooler, and condenser out. We see these trucks have radiators plugging up with dust between the fins. They look clean from the outside. We have these blow guns with long snouts, with like 5 or 6 vertical holes. You slide it down between the radiator and charge air cooler, blowing the radiator out with shop compressed air. Then turn it to the front to blow the condenser and cac. Take your time get all areas.
I uploaded a video just a bit ago to show you what I do. It's a short video... I'm mostly talking about improving AC performance, but it applies to the cooling system as well. The vehicle I was working on actually ran at 230F ect just driving down the road unloaded. So it's just a suggestion, give it a try.
https://youtu.be/NoB_53lcz7Y
I'm sure your also aware of clogged oil cooler performance. Anytime you see EOT more than 20degrees hotter than ECT, its likely time to change it. Your temperatures (235 and 225) looked normal as far as that's concerned. Once you pass 40mph or so, the fan really isn't capable of moving much more air than what's being forced through the radiator by surrounding air, and then becomes a large parasitic draw on power likely leading to even hotter temperatures.