Let's list the mission requirements for a Landscape Photography Vehicle. That'll help us decide.
1) Accommodation. If you're not on location at dawn or sunset, you've missed the best part of the photographic day. Sure, getting up at zero dark thirty in a motel room and driving fifty miles in the dark in order to arrive at the location at dawn works. Once. You have the same problem on the other end of the day. Exiting a location a half hour after sunset and finding a place to eat and then a motel is equally dysfunctional. That procedure also interferes with the "getting up at zero dark thirty" concept the next morning. Heck, it's ALREADY the next morning.
So you need a vehicle that provides a good night's sleep. Preferably night after night. Right at the location. The closer the better. If you awake near dawn and you can see by inspecting the sky that the light's gonna be crap, you roll over and go back to sleep. If the sky is tinted rosy pink and there are hints of high altitude cirrus, you spring from the sack and fire up the stove for coffee and when the light arrives, you're out there, ready.
2) Sustenance. You need to eat, preferably something tasty, nourishing and healthy. Without it, you're not going to be at your best, work-wise. That means you need a kitchen, however primitive. If you're careful, you carry enough food and water for several days to provide for emergencies. That means at the very least, a cooler of some kind, a stove, pots and pans and secure food storage.
3) Transport. That's the whole idea in the first place, right? The vehicle must provide comfortable, economical long distance highway transport. Forget special purpose off-road vehicles. 98% of your driving will be on paved highway and most off-road vehicles are intolerable at highway speeds. If we're talking transcontinental missions, these constraints become even more important. If you absolutely have to get away out there, walk, get a bicycle or take a small motorcycle. All of those will go where no 4WD would dare venture. With a few exceptions, there are very few locations that only a 4WD vehicle can access. The noise, vibration and harshness penalties invoked by 4WD vehicles are simply not worth it, IMHO. And don't get me started on fuel economy.
4) Dwell time. Let's face it. The skies are not always filled with mare's tails. You sometimes need to just sit and wait, maybe for a day or so. Sitting in a motionless vehicle for a few hours can get old fast, so you need to carry a certain minimum of furniture. A lawn chair and a small table completely transforms a location, any location, from a parking spot into a living room. Add a book and some tunes and you're golden. Ansel proved repeatedly that the best time for landscape photography is during a clearing storm. That means that you have to be there during the storm, right? Hopefully, the interior of the vehicle doesn't become a prison while you wait out the wind and rain. For that, you need space.
5) Security. Many of us have several thousand dollars worth of camera and computer gear aboard so any vehicle that draws attention to itself is out. Above all, we need anonymity. Inconspicuous is us, especially when our overnight locations are in urban areas, as is sometimes necessary. A Land Rover Discovery, while a capable off-road vehicle, is a thief magnet, as are most Jeeps and the like. I want to be able to blend into the landscape and be invisible - hiding in plain sight.