Good to see you like the pictures.
"How far away from civilization does this wheeling take place?"
Iceland is a small country, when in the middle (furthest away from civilization) there are never more than 100 miles. But dont get fooled, when conditions are at its worst it's completely impossible to move the vehicles due to crazy weather. And the snow can be so tought to drive on it can take hours to drive 1 mile in worst cases.
Regarding the amount of fuel. Tank capacity is 80 liters, barrel at front end is 60 liters and often i have 4x 20 liter jerry can's in the car. = 220 liters = 58 gallons. Typically I use maybe arround 40-50 gallons in a weekend but up to 80 in the longest trips
"Get rid of your pesky gas tank, move the axle 8" backwards, and you are ready to drive to the volcanos.." Funny thad you say this, most of the mountains I drive on are volcanos, some are active and even errupted last several years Like these:
Taken at the top of eyjafjallajökull which erupted 2010
taken on fimmvörðuháls, also errupted 2010