From May 8, to May 30, 2010, I was travelling in United States on the "Best of the West" tour offered by Trek America. Although the group was older than expected (with an average age of about 50), the mix worked really well – in fact, even better than I could have wished for. So, the age did not really matter after all.
What turned out to be (much) worse than expected, though, was the weather. We experienced pretty much everything you can imagine: from hail to rain to snow, from sunshine to strong winds (including a snow storm, and a sand storm). Despite these adverse conditions, however, it was a really great holiday.