Hi,
My husband and I are also going on the U.S. National Parks tour in May (leaving the 15th). I was hoping to find someone who had prevously taken the May tour and who might be able to suggest what to pack. After looking at the temperature guide for Grand Canyon National Park, Salt Lake City, Jackson Hole and Sedona, it seems we may need winter coats for early morning and evening, but it looks like summer clothes may be in order by midday.
My girlfriend and I used Go Ahead Tours when we took the Walking Through Tuscany tour a few years ago and thoroughly enjoyed it. We were lucky to have travelled with a really great group and our guide (who was fantastic) even suggested a couple of alternatives that he thought the group would enjoy. We are looking forward to this vacation and I am expecting that Go Ahead Tours will not disappoint.