“A sign at the gas station notes the next nearest station is 40 miles away to the north and 12 miles to the south.”
I’d charge more given those circumstances.
40 miles north there are least 5 gas stations charging normal $4.50/gal prices.
Back in the 80’s there was a sign on a road in South Texas just south of Corpus Christi. It warned driver not to pass that point without at least a 1/2 a tank. They weren’t kidding.