One of our best trips was from Phoenix Arizona- up to Sedona- in red rock country- we stayed in Sedona a few days and it was magical- then up to Grand Canyon, and on to Arches, and Mesa Verde, Canyon de Cheilly and then on to Colorado, over Berthoud Pass and to Grand Lake and Estes National Park and return via Denver.
The other trip we did was via Boston and Cape Cod, then all the way down to Williamsburg, Virginia, with a few days in the first ever National Park, Sky Line Ridge and the blue mountains- memorable for us as it is where wer encountered our first wild black bears, a mother and 2 cubs up in an oak tree.
We would love to do the West Coast up from San Francisco, via Montana and up to Vancouver Island and the Rockies- one day.