New Truck Purchase Any Advise

[JHNDZ]

Im currently looking at a 2015 ProStar with a Cummins ISX. It has 450xxx miles, I found it in
Knight Fleet Truck sales. It's a beautiful truck and I'm very interested in the purchase.
Can i get some advise on what to pay extra attention too. I do have Insite and will be looking at the basics like Regen history, injector performance, but is there something more i can do ?. I am limited on some things with Insite so any help will be appreciated.
How can i tell if its consuming coolant ? or oil ?
Is this yr. affected by faulty fuel pump ?
Is it better to see original parts like turbo,dpf,scr, or is it better if they've been replaced?
what should i consider red flags ?
is Knight known for good fleet maintenance ?