As a Colorado resident, I highly recommend you get a 4WD if you are driving in the snow and ice. A 2WD SUV - i.e an Expedition - is worse than a 2WD car in the snow. I was just driving in the Colorado mountains this past weekend in the snow and the two cars I saw having the most trouble was a 2WD Honda Pilot (the damn thing just spun in place) and a 2WD Escalade, which almost hit my car a few times.

If they have no 4WD and you are offered a 2WD large SUV, I'd kindly ask for a 2WD car instead (make sure it's FWD). My Honda Civic FWD car is a champ in the snow.