> I don't even know what an elliptical machine is, however if her experience means anything, it isn't much help for hiking.
Depends a lot on how she uses the elliptical machine. If she just loafs along on it all the time, then I can see what you are saying.
OTOH, if she does an appropriate mixture of workouts (aerobic, anaerobic threshold, intervals, etc) on it, then the machine should be quite a help.
As with most gym-based exercise regimes, using it most effectively takes enough intellectual effort to figure out how to (or assistance from someone who does know) and then discipline and physical effort to make it happen.