Just returned from another 2,500 trip through the desert southwest. Eighteenth such trip this year alone. Ambient temps from 50*F to 118*F. Sea level to 7,000 feet finishing off rolling 75-80mph through the Mojave Desert.
Replaced trans at around 280k just because there where multiple leaks that would cost almost the same to fix them with R&R of trans.
Little later... replaced v. pump, water pump, center driveline bearing, rolled on a new timing chain, etc... Added a trans cooler and lower thermostat for the desert heat....just routine stuff.
Best upgrade: Tinted the windows. Huge help with the limited A/C performance when the temps outside get over 100*F.
Cool thing is I don't think twice about taking off for long trips. With a little common sense and TLC these things just roll & roll & roll
P.S. Tips from this group make it easy to keep it rolling!