Nice. I want to get out there. Might try to take my own 2-3 day trip out there in late March or April. A bit nervous about whether or not I will be one of those susceptible to altitude sickness but i guess that is something I will see if/when I get there.
Meh, don't sweat it. Like you said, there's only one way to find out. Be in good shape and stay hydrated to minimize it, but some people are just plain more susceptible to it than others, regardless of their physical fitness.