Tearing it apart...

[ford_cummins83]

Made a 700 mile trip to pick up a trailer, started heading back and my eot and ect were up to 35* apart, so I got home and thought I would flush the system before I made the same trip two wks later, I flushed it with Prestone flush and simple green about 4 times, and then just straight water which looked really clean in my bucket. Filled the trailer full of my stuff since I was moving and on the way my difference kept climbing an went as much as 58* difference between the two, this was at 2am so my choice was to try to make it and see what happens, today I unhooked the trailer and drove down the highway and just empty it shot up to 28* difference.. My fan clutch had been out since I bought the truck last summer, so it's time for it anyways, and I won a alligator egr delete at a raffle for 1 dollar lol, so I figured I may as well tear it apart and do the oil cooler as well as the other items. My question, should I flush it out now before I get the parts or after or both? And what else should I get while I'm there?
On order are the fan clutch, bulletproof waterpump, oil cooler and Stc fitting and then I have my egr delete and already haven dummy plugs and pipes