Originally Posted by
Midwest Michael
While Avis can't guarantee that your SUV will have 4 wheel drive, I can give you a 100% guarantee that taking an Avis vehicle off road will be a violation of your rental agreement, even if it a 4x4. A Ford Escape also isn't really designed for off-road driving, even with 4 wheel drive. Utah does have lots of opportunities to go off-road, but you need to contact a Jeep Outfitter where you can rent a truck actually designed for off-roading for the day.
Renting a sedan will likely be a much better value than an SUV, which usually carry a pretty significant premium in cost.
I would be a little surprised if you find air or water tours out of either Flagstaff or Williams. Any boat tours are going to start around Page. Air based tours are likely to start at Grand Canyon airport, which is near Tusayan/south rim. Also be aware there are air space restrictions within the national park, which don't allow helicopters to go down into the Canyon. That often means that helicopter tours do not actually visit the National Park, but rather Indian lands where the canyon is not as deep or spectacular - although that is a bigger issue with tours based out of Las Vegas.
My last visit to the Grand Canyon was in mid-March and it was very comfortable - with temperatures in the 60's, I believe, although it gets quite cool overnight, and there were still some patches of snow on the ground. Of course, that doesn't mean that's what you'll see during your specific travel time.