Add two game modes "Hardcore Simulation" and "Normal"

There seem to be two lines of thought here when it comes to strictness of the game. There is a simple way out:

Just add a way to adjust all possible values, as size of the quarry, amount of sand in the truck, fuel consumption of vehicles, damage in wear and tear or damage in collisions, all that stuff... 

Then add a "normal game mode" the values add to what you think is fun and in which sliders and switches allow players to adjust those values or just outright disable fuel consumption or damage.

Then add a "Hardcore Simulation Mode" where the values are a bit more realistic, the quarry size is just the quarry etc and the sliders cannot get adjusted at all. Give people Achievments for completeting objectives in this mode.

You can switch freely from "Hardcore Simulation" to "Normal" - but not the other way around. 

That way, everyone is happy and the workload should be managable, as you have those variables anyway. They just need to get exposed in menus.