I've read a lot of reviews that say you can drive to the lower canyon. Do you need a jeep/SUV or can this be done in a rental car? Also, we were thinking of doing a preplanned photo tour (still struggling over which company given the mixed reviews they all have) at upper and then independently going to lower and getting our guide there so that we can have a more "private" experience. Is it a waste of time to go to lower if we've already done upper? This will be mid-August.