Better to reply late than never, but we took our kids up last summer at ages 11.5, 13th birthday, and 14.5. None had a problem, but we hike quite a bit. Get them out on a few steep bay area hike in the next couple of months, and you should get a good idea of how it'll go (e.g., Mt Tam, Black Mountain in Cupertino, Mission Peak in Fremont). Oh, and cellphones worked surprisingly often, including Nby scottpedition - Yosemite and the Sierra Nevada. News & Discussion