I think the range of different prices for fuel is a good idea, but I feel like the current values don't serve making things interesting in a lot of cases.

In Michigan, the two easiest-to-access stations are the cheapest at 2/L. The one at the back of Drummond Island - the hardest to reach - is 5/L.

On the one hand, I see a logic to this - you have to take fuel supplies with you to the harder-to-reach places if you want to avoid high cost refueling.
...on the other hand, it might provide a better overall challenge if fuel was cheaper in the harder-to-get to places, and more expensive in the most-frequented area... then you'd be incentivised to "import" fuel from more difficult areas.

It's more pronounced an issue in Alaska - two of the three cheapest stations are the roadside station at the north of North Port (right between the gateways to two other maps), and the roadside station in the middle of White Valley - two of the most central locations to most of the missions. There's very little reason to even bother with fuel trailers there.

Taymyr is pretty expensive all round, but again, the two super-easy roadside ones are cheaper than the off-the-beaten-track station at the south end of Drowned Lands.

Kola is ideal, as it only has a single station right at the start, so it's a logistics challenge the moment you run out the free fuel from trailers on the second map.

Thoughts?