I agree with the other answers here...and would also point out that you can often find a nice external frame pack at a thrift shop. Saw one the other day, a Kelty that weighed under three pounds and was for sale for $6.

Can't beat that, especially for the kinds of trips you are considering.
_________________________
Check our our website: http://www.backpackthesierra.com/

Or just read a good mystery novel set in the Sierra; https://www.amazon.com/Danger-Falling-Rocks-Paul-Wagner/dp/0984884963