I agreed with Pilot and Flying J. Google street views is how I plan most new trips, especially if traveling smaller roads. It gives me some level of comfort that I am familiar with the roads and turns.
I also try to fill up BEFORE getting to camp at the end of the day. Better prepared for storms or others situations if the park loses power and I need my generator.
I have also used the KOA trip planner when covering lots of miles. Most KOA's close to the highway are also close to a larger gas station.
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