You don't have to get too carried away. Preventative maintenance goes a long way. The boy scout in me wants to have enough tools and parts to build an engine on the road. Be Prepared. But in all actuality I figure I have driven a little over 500,000 miles long haul before I quit. 4 times i have been stuck on the side of the road. Heater hose blew. Flat on steer tire. Water pump went out. Blew radiator hose. I did lose a turbo once but luckily I was close to a truck stop. So really you don't need to go overboard. Have enough stuff to fix the small stuff. The big stuff you will not likely be able to fix on the side of the road anyway.
I have to keep telling myself No you don't need every wrench you own. 2 of each size is plenty. No you don't need 5 hammers. 2 is plenty. Why are you bringing 40 screwdrivers? Put half of them back.
The boy scout in me did win the argument about the extra air compressor. I have a little one from harbor freight I use to carry. Now the truck has a built in one. Don't need it. But if the truck compressor goes out I can hook in the little electric one to air up the truck.