A tailbone pad for the newbie snowboarders is a good idea. They will spend considerable time on their butt and a bruised TB can wreck a vacation. It's been a couple of years since I have been skiing but last time I do remember tiring more easily and the knees were well off their prime. We used to run with the "ridges and chutes" crowd in our youth.
http://www.xsportsprotective.com/pages/how-to-choose-snowboard-padded-shorts