Not sure if you have your heart set on that HMB stop. You have a short leg from Redding to there, and a really really long leg from HMB to Hermosa. If you wanted an overnight stay a little further down the road, Prewitt Ridge is about a half hour south of Big Sur has some great dispersed camping options with amazing views. It’s about a 25 min climb from the highway, but you’ll be sitting at 2700 feet with some awesome views. and of course you’d need to have your own water, etc as there are no facilities up there. Just did a two night camping trip there a few weeks back and it did not dissapoint.