It is really far, 10.5 miles one way...21 miles round trip. I think some hard core people go to Glacier Point and back in a day, but I don't know how they do it. 10.5 miles was more than enough for me. It probably took us 5 hours one way on XC skis and it was exhausting. The weather was pretty bad (rain) on the way there and made it kind of difficult to ski. The next day the groomer went by, so that made it a little easier. There's a big hill to get down to Glacier Point and then you have to climb back up it to get out, obviously. You should know how to XC ski before doing this trip and be in shape, maybe go XC skiing once or twice that season to tone up those muscles. We went to Bear Valley a couple times to take a lesson and XC ski before going to Glacier Point. They have a nice XC ski area at Bear Valley.
You have to book a trip in order to stay at the lodge at Glacier Point. Otherwise you're snowcamping.
http://www.yosemitepark.com/BadgerPass_CrossCountrySkiing_GlacierPointHut.aspxAll I can say is it was worth the price.
Bring earplugs for sleeping in the bunk beds!
You can go do Dewey Point for a day trip if you can't make it to Glacier Point.
I think Crocker Point is popular, too, I think that is a little closer.