After I settle in my camp/hotel or whatever for the evening, after having a fire and or while having a few drinks, I'll usually play around on google maps, just to see where I am, where I expect to be the next day, and take a couple notes about the next days first fuel stop and roads to take.
Sometimes I gas up in the mornings when getting underway or shortly thereafter. So having the first fuel stop planned is very important. Other times if I'm hoteling it and there's gas near where I'm staying, I may settle in then go back to fill up, get some food and drinks and call it a night to be ready to gun it in the am. I'll always look at online maps and routes in the evening though just to frig around and relax.
If I continue drinking I put my couple notes in my tankbag before I'm too drunk, so I can be reminded of what I did the night before.