Awesome! Sounds like an excellent road trip.
I probably wouldnt be too worried about EGT stock, however I would get an aftermarket temp gauge on there even if only for the trip. I would start by making sure that cooling system is as good as it can be and watch it.
As others have stated, in Colorado, low horsepower naturally aspirated vehicles can struggle on inclines mightily. My FJ55 on 35's was like 30mph climbing grades outside of Denver and Ft Collins

Take it slow, don't push it and you will get there. I just did a 2,400 mile round trip (not in my Land Cruiser

) and honestly it's hard to recall any of the sights because it was hurry, push it lets go! When I take my cruiser, I'm looking all over, driving slow, not stressed and just enjoying it. And yes I get the dirty looks occasionally too because how dare I drive 60mph in a 65mph zone!!!!
I would just make sure you have a few spares of important things that you might not be able to find at any old store.
As for cooling if it were me going on a whirlwind adventure across the US... I would seriously replace ALL coolant hoses and flush now if they haven't been replaced. Replace the water pump as well. Make sure your fan clutch is working right. Unless the radiator is fairly new, I would take it to a shop and have them test/clean/unclog/repair.
belts - slap new belts on, use the old ones for spares
Radiator hose patch kit - or you can use your old hoses as spare as well
full size spare tire
Tire patch kit
Fuel filter - never know if you get a bad batch of fuel
Diesel treatment, you never know
There are more spares and things to bring on the trip, but heat is the killer of these 3B's. Make sure they are cooling good, especially with extra people and weight going to the mountains.
Sounds like such a great time!