Geologists and other field types are opinionated about their vehicles. Often if we're taking a bunch of stuff into the field, we need something with more storage space than my hatchback. So there are a few options.
If you need a huge amount of stuff (or just some extremely large stuff that you don't want to get wet), then you're stuck with a box truck. But most of the time with environmental investigations, it's a pickup truck or a SUV or a van.
I'm not a big fan of the pickup truck. If you are transporting a bunch of coolers or equipment, then you need to worry about keeping everything dry and make sure that nothing goes flying when you get above 30 mph. Also, unless you have 700 pounds of gear in the bed, the handling and traction are atrocious. Many of my male coworkers, however, had strange masculinity issues and were only comfortable with the largest, beefiest pickup trucks (and they had very specific ideas about Ford vs. Chevy... there are no other truck manufacturers).
If I can fit everything inside, my preference is an SUV - something with ground clearance, that's not too heavy or so big it won't fit down your average logging road. But if I'm carrying more than, say, 5 coolers or a few pieces of equipment that can only be loaded in such a way that they have the potential to fly through the back window, then an SUV won't work. Then I'll take a cargo van.
All the cargo vans I've driven have had anemic engines (as in, you can't even pass a loaded tractor trailer in the "truck passing" lanes on hilly back roads), no CD or MP3 player options, terrible sightlines, and terrifying handling. But they can hold practically as much as a box truck if you really jam stuff in, they have almost the same ground clearance as your average SUV or pickup truck, you can fit long, pointy things (like pry bars and hand augers) on the floor without fear of getting skewered in an accident, and you can get practically the entire field crew camped out in the back if the weather goes south. And cargo vans are surprisingly adept at off-roading - you can take them practically anywhere, and they're so light (if you dump out all your field gear), you can easily push them out of any trouble spot you got them into. And nobody really cares if you scratch a cargo van.