Need help planning a road trip out west?

So my boyfriend and I are thinking about taking a road trip from Wisconsin to the western USA at the end of August, and we need some advice on where to go. We're both pretty energetic individuals that love camping and hiking, and we're really interested in seeing the classic national park sights and geological features like the Grand Canyon, Old Faithful, or the Mesas. However, my conception of distances between some of these places is pretty poor and I'd like some help planing an itinerary from others who have actually been there before. Thanks.