usually the fear of hitting a deer, or moose, was enough for me. Driving overnight to Champlain on NY thruway cruising through the Adirondacks at 1am, not seeing a car for long stretches at a time. or when I was commuting regularly from NJ to ME.
I'd always buy 2 white monsters, 2 packs of planters honey roasted peanuts, and a bag of sunflower seeds. I don't drink caffeine normally, so these are like crack... I imagine. I'd drive the half (4-5 hours) drinking water, then I would open a monster and peanuts when it got boring. And the other was backup if needed.
On a actual busy highway like 95 or merit parkway, seat down, lights dimmed, cruise control, windows down and music up. When the air on your face starts to feel good, it's time to pull over.
Biggest thing was up tempo music, hard to talk when arriving at location some times, had to put on an overnight concert to keep moral up.