It's just north of Yosemite, and much of the terrain has some of that same wonderful granite. you can easily find a five day trip there--we've got a few of them on our website under the destinations section: backpackthesierra.com.
But beware! Late October will almost certainly mean snow on the ground, and it's really only a question as to whether you are going to see 3 inches or two feet. Anything over about three inches will obliterate the trail---so if you are not comfortable navigating without a trail, stay out of the mountains.
And it will be cold. We had temps down into the low 30's two weeks ago. It could easily drop below zero F in October at elevation.
The alternative might be something like Henry Coe State Park south of San Jose. It's quite large, and while you won't be hiking in the Sierra or getting over 5,000 feet, you can certainly spend a few days exploring the coast range...and living to tell the tale.