A couple of things to consider: Due to fires last summer, royal gorge in CO may be closed. Call before you visit it. DO take the Durango/silverton train! Lots of fun and very scenic. If you are pressed for time take the train to Silverton, and the bus ride back to Durango. While in the area, drive the million dollar highway over red mountain pass (us 550). Very scenic! Also, if you have time, have a jeep company take you over Black Bear Road into Telluride. Not to be missed! In Yellowstone, try reserving a site in Bridge Bay campground. No hookups, but more room between sites than Fishing Bridge campground, and the ranger program is great. My two boys, 10 & 14 really enjoyed it.