There are two gates on Horseshoe Meadows Road. The Inyo county roads department closes the lower one for the winter, and opens it in April usually. They need to clear all the rockfall each spring. The upper gate is a half mile from the Cottonwood Lakes trailhead, and I believe is controled by the USFS. It is near the 10k elevation. People park at the gate in the days before it is opened. You could park and spend the night to acclimate there -- Overnight by your car, or maybe walk the last half mile and setup a quick camp site.

Here's the thread from last year concerning the gate. Horseshoe Meadows Road