Not sure is it the right word... But I got an idea.
Why don't put an option at the laps chooser, named like Endurance or something else. It would be like this. You turn that on, and fill the fuel to the end, so as the AI's. There should be no lap limit, you just drive as much as you want. AI's would just drive (if you would drive 48h, they would too). And possibility to make some setup changes while the race is going. But not all, so the reallity stays on. I hope you guys understood this idea.


EDIT: I think this is good because if you want a long race, you need to click on the lap counter for half an hour.

It took me 24 clicks to set a race from 0 laps to 48 hours. Just click on the arrow with the right mouse button.

Edit: morpha's post

Guys, /laps or /hours

It doesn't matter. With this you could drive with no need to finish first and you would be more relaxed... At least I think so.

It's called practice mode.

It's not meant to be like that, and in practice mode you don't get your car repaired.

I'm pretty sure you do - check your F12 screen and stop in a box, it'll be done...

I always get a message: "Car not fixed in practice." Or something like that, I have that on Yes... At least I think I have it on YES.