Pickups have weight distribution issues…though in SoCal that is probably not as big of a problem as someplace where it snows. Any truck-based SUV should do just as well as the 4WD pickups they are based upon, will probably be a little bit safer, and may get marginally better fuel economy (pickups have terrible aerodynamics, too). Don’t limit the search to pickups unless she will actually need to be hauling large things or dirty things. And fortunately for you, whatever you buy it’s a buyer’s market for trucks.
And if you know how to ride between the ruts, a Subaru will probably work. That’s a big if, especially with a teenage girl, and even then I say probably because I only have your description to go on. Actually, depending how bad the mud is, and how deep the stream is, ANY car may work if you drive it right, but 4WD does make that kind of driving less of a white-knuckle experience.