Good question my friend, I personally have no idea as yet, but i expect it will be costly.
It has already been fitted with an external tank that will hold 300 liters, giving us 400 liters in total, and if the worst scenario was 20 liters per hundred kilometers, we should get 2000 kilometers with the full fuel load.
I have been told that fuel across to the West can reach double the price, so we hope to drive past that lot.
I will just pull into Dougie's servo, (dugnsuz) on the way through
Leon