Good questions...
Some answers:
1) Where can you camp:
Lone Pine Lake
Outpost Camp/Bighorn Park
NOT at Mirror Lake
NOT at Trailside Meadow
Consultation Lake (recommended due to lack of people)
Trail Camp (lots of people there, but look around and find secluded spots)
Near the junction with the JMT
At the summit
2) Ok to sleep in the hut?
Yes. There is room for 4. People hardly ever camp at the summit. Sleep outside if the weather is calm, and enjoy the stars. Use the hut if it is too cold or windy.
