I get altitude sickness fairly predictably, but I took a train from Interlaken to Murren to Jungfraujoch in the Swiss Alps this summer, summiting at 11,322 feet. I experienced no altitude symptoms. Harvey suggested that the ease of sitting on my haunches while scaling the mountain would likely make the ascent easier and without AMS symptoms. He was right. 14K would worry me a lot more, but my experience taking a train to 11,322 feet makes me wonder if my reaction to flying into an airport like this would be less traumatic than hoofing it up a 14teener.