There is no problem driving the roads in any size motorhome - I've driven a 40 footer through there - but parking is a chore in any size vehicle and 25 ft just adds to the difficulty. And you do a lot of parking to see the sights, including just pulling over to the side of the road when a bison or elk takes a stroll in your path. Often there is only a dirt pullout - or less. Even the views with real parking lots aren't roomy. I'd get the car if that is an option - it makes the sightseeing much more enjoyable. If not, well, you will manage.