I have skated this in a couple of hours on multiple occasions as well as having skied it in a couple of days and stayed at the Glacier Point Ski Hut. No matter how you do it, this is a fine cross-country ski tour.
Starting at Badger Pass you have a climb for a bit less than a half mile and then you descend gently to Summit Meadow and eventually to Bridal Veil Creek at 2.8 miles out. From here you have a gentle rolling terrain with nice meadows until you get to the base of the incline up to the Sentinel Dome plateau. This climb is never steep, but lasts a few miles. The road also tends to slope to the side in many places as well, which makes no difference for striders, but can really hit you on the downhill leg as a skater. You will gain around 2000' in elevation between Bridal Veil Creek and Sentinel Dome.
At about the 2/3 point, you come to Ostrander Rocks and a wide open view of the Clark Range. Another mile or so finally gets you to the top of the hill and you're treated to a relatively flat ski out to Sentinel Dome. This part of the tour is a real pleasure for skate skiers. Sentinel Dome itself is an excellent side trip with great views in all directions and, in good snow, some fun descents on the Yosemite Valley side of the dome. One thing to note: in the winter, you do not approach Sentinel Dome from the normal trailhead. Instead, follow the groomed road to a point where it turns right, and there is an ungroomed road going straight. That's the easiest way to Sentinel Dome.
Once past Sentinel Dome, you have a continuous descent of almost 1000' to Glacier Point, which is great fun though if you're skating it's a nasty skate back up. Along the way you'll pass Washburn Point with excellent views to the north and east and eventually land at the hut itself. From there it's just a short way out to Glacier Point proper, though in most conditions it's usually easier to leave your skis at the hut. The hut is locked and is only open to clients on guided trips, so don't count on refilling your water bottle (they truck water in for their clients). If you're on a guided trip and staying in the hut, you'll find a warm fire, so you might as well head out down the Panorama Trail and take a few turns down Illouette Ridge. It goes without saying that you should not go over any blind drops as some are express routes to the Valley.
From here most people just turn around and retrace their tracks, but strong skiers can also descend to the Valley via Le Conte Gully (which is not the official Le Conte Gully, actually, but the one that ends at the Le Conte Memorial). This is a pretty steep descent and only something to be attempted by expert skiers and snowboarders, and not on cross-country skis.
Glacier Point Ski Mileages
I keep writing these down and losing the sheet, so I'm finally putting them here so I'll know where to find them. And now you will too.
|Top of hill west of Summit Mdw
|Top of hill east of Summit Mdw
|Top of 2nd step west of cmpgd
|Top of Hill first step west of cmpgrd
|Bottom of Clark Range Hill
|Clark Range View
|Top of Clark Range Hill
|Top of hill by Sentinel Dome
|Final Top of Hill
|Top of Steep Part to GP
| Lookout Closest to GP