If I remember right (it’s been a few years and you have made me think) most things were gas so they could all be filled up from the same truck and there was never any confusion, they’d fill trucks/generators/light poles/heaters all from the same unit. You could get diesels but you’d have to drive them to a specific location or leave them somewhere to get filled up. So both diesels and gas trucks would be idling all winter.
Normally pretty low, very few of the rentals I drove made it above 30k, the distances driven weren’t very far but the engine hours were really high. They were put in low idle and sometimes left for days without being moved and even if they were they were driven about 2 miles. Frozen brakes was always fun.
I worked in Alaska for 5 years, in the winter if we didn’t have anywhere to plug in block heaters so the oil wouldn’t thicken up we used to leave the trucks running for months at a time. The rig used to have a guy who’s only job was to go around and fuel up all the running trucks and generators. Probably left a rental truck running for 15 straight weeks.
On the slope, so we had a few of our own trucks but a bunch of Delta rentals every winter for exploration season. They would have 3000 hours after 4 months.