You could also do Onion Valley one night (reservable), then move south to HM on night 2.... or try to get a walk ins @ Rock Creek Lake then move to HM.
Here are some photos from Little Lakes Valley, just up the road from Rock Creek. LLV is one of my favorite places:
http://www.hikinggeek.com/2013/08/16/little-lakes-valley-trip-report-august-16-2013/
