I've made 3 cross country trips in an Escape 17B (as well as many prior trips in a minivan & tent). The most enjoyable have always been those that used the secondary roads & had enough time to "stop & smell the roses". You lose so much knocking off 500 miles per day on the interstates.
As to my favorite areas, it is hard to beat the Southwest. While my favorite national park is Glacier in MT, and my favorite state park is Ricketts Glen in PA, the advantage of the Southwest is the variety & the many state & national parks.
I realize that many must rush to "get there" within limited vacation time, but if you have the time, my suggestion would be to use it for both the travel & the destination.
I have made journals of many of my trips - links to them are
here.