Originally posted by DanFromDetroit
Are you going to build her a canoe as well ? 
It seems to me that you intend on going to alot of trouble for one afternoon's worth of cycling for charity.
If it were my g/f, I would take 1/3 of the budget and buy a disposable MTB from a local big-box store and take the other 2/3 of the budget and donate the money to the charity or spend it on a post-event party.
Riding with her and snapping a photo, or otherwise documenting her effort would be a nice gift as well.
Good luck and have fun.
regards
Dan
Its clear that neither you nor pokey have bothered to take the time and trouble to read the brief properly or the following discussion. Leastways you would appear not to have fully understood.
How many of the novice ladies of this forum do you think could race a heavy MTB up and down 50 miles of mountain roads and rough muddy tracks carrying it over gates and obstacles and up hills.
Then get off and run up a 3000 foot mountain and back down
Get on the bike ride to a lake and paddle a 2 canoe raft around a 1.5 mile lake after that all in under 8 hours! and trying all the while to keep up with 3 fit male army team members. Get real
If you cannot be bothered to respond helpfully please don't bother at all.