Believe it or not, many geos and land people out here use Expeditions for off-road travel. After doing my geological work in Nevada for over 30 years with F-150s, I have learned a few tricks... like not getting in too deep and not walking out. If the terrain looks beyond what the vehicle capabilities are, I walk to where I need to be.
The OEM Hankooks are not only street tires, they are rated AT, all terrain. BUT they do only have 2 ply nylon sidewalls, which is a concern of mine. But if I get a flat out there, I will replace them. Until then, it is an experiment. The Expy was built for the road as well as the off-road.
Try it, You'll like it!!