As you'll probably know the artist formerly known as the G-Wagen has been around since 1979 and we have the latest G350d model here, complete with 245hp 3.0-litre V6 diesel and seven-speed auto. To help when the tracks turn into bogs, the Mercedes has three locking differentials, a low-ratio transfer 'box and Atturo Trail Blade tyres. There's also 442lb ft of torque from 1,600rpm and, aside from the optional paint, heated steering wheel and sunroof, the only other change to this £104,000 SUV is the removal of the sidesteps to aid ground clearance.
That's the car, so what about the route? It starts on the rocky shore of the Cromarty Firth, complete with sleeping oil rigs in the background. From here, it's across fields, under the A9 and on to the first of many forest tracks. Our initial goal is the Fyrish Monument that we can see on top of a nearby hill.
GLE and GLS but mostly G-Classes, is unstressed. A quick stop here so the local dog walkers can wonder what we're up to and then it starts to get much harder. A very steep descent requires low ratio and a locked centre diff, which isolates the ESP and ABS to provide more traction when these systems might otherwise hinder progress.
Unlike the GLE and GLS, the Gelandewagen doesn't have nearly as many sophisticated electronics to keep it moving forward in a controlled manner. It doesn't need them, either, as throughout our whole 12-hour-a-day stints it never once scrabbled for grip. It also helped that the chunky tyres were running lower pressures than would be possible on normal roads, to broaden their foot print and spread the 2.6-tonne weight of the Mercedes more widely.
Dropping down into the glens, the freezing cold at the Fyrish Monument gave way to milder temperatures, but this also meant wetter conditions. Deep ruts, standing water and boggy stretches offered the first real tests for the G350d and it came out muddy but unbowed. The ground clearance of 235mm was sufficient to avoid damage to the underside of car, while bash plates protected the sump and fuel tank.
The next morning, we set off early to beat the weather that's forecast the first heavy snow of the Scottish winter. Driving out of Alladale, we headed on to a section of tarmac road that felt alien after the previous day's tracks. Closed to the public, it offered the perfect opportunity for a bit of competitive driving in the form of a regularity trial.
Regularity as clockwork
With a target average speed of 18mph, co-driver Matt Prior from Autocar and I set a reasonably brisk pace to compensate for the slower sections. We didn't know where the finish line was going to be, but nearly three miles later we crossed it and were back onto unmade lanes. Thankfully, PH and Autocar honour was upheld and we beat the other 11 cars to claim first place.
After that, we spent the rest of the day picking a path through jagged rocks that would shred the tyres. This goes a long way to explaining why it took two long days to cover 65 miles from east to west coasts, but every minute was enjoyable. The level of concentration required to keep the G-Class moving in the right direction is just as absorbing as driving on a track day. Different disciplines, but the same sense of satisfaction.
Rolling into Ullapool as night closed in, we tip-toed over the local golf course to dip our tyres in the west coast's water. Knackered, yes, but also with a rejuvenated respect for the off-road ability of a vehicle more recently associated with urban posing than the job it was built for. And can still perform.