My 2 cents:
1. Running prepared me for Whitney (I had one hike all season, but many miles of running) but hiking Whitney would not have trained me to run. (I did not do it as a day hike, but as relaxed/moderately refreshed as I felt on the summit arrival, I feel I could have done a dayhike with just a little more prep)
2. 2 days of acclimatizing (dimox even better) took care of the altitude with zero negative symptoms of AMS, but no amount of passive training could help my running.
3. I could hike Whitney with running as a base, but walking a trail would never be enough to prepare for a marathon. In sheer dedication of time/effort, a marathon would take much much more.
