I have to say that spending a night at the Mammoth Mountain Inn the night before camping at the Portal, made a big difference in the hike.
9000 feet is pretty high up to be hanging out for 18 hours, after being used to sea level. But the comfortable beds, hot water and full hotel amenities, made it possible to get a good night's sleep in spite of the altitude. Previously we had spent some hours at Horseshoe Meadows but it's nearly impossible to sleep without acclimating first to go there, so it defeats the purpose (what's the point in trading off valuable sleep for acclimazation?).
And the night before the hike I was able to sleep well for the first time in the Portal campground. I was very surprised and happy about that.
