If you don't use the radiator cooler you need a really big auxillary cooler. I hope you selected one between 20000 and 30000 pound towing capacity.
35000 lb GVW rated cooler, and adding the fan should make it nice and cool consistantly. and as for the power steering no, it's fine, full of fluid, just wondering if you guys have relocated it from it's ugly position where you placed it? thinking about getting a second trans cooler with pusher fan for it, i know it's overkill but a nice matched set would look pretty sweet, just have to adapt the lines i think, and of course the system will use a bit more fluid... heh
Whether it is overkill or not if you feel the need then go for it. Keeping oil cool is never a bad idea unless the temp drops below 120F - then it will collect moisture. That is bad.