I enjoyed your pics. Always amazing to connect with some wildlife, especially on solo trips.
Redwood NP is not on I-5. It's on the coast. If you take I-5, you could go through Lassen. A lot less steep than the Sierra, but many pretty lakes and lots of good day hikes if you don't have time to backpack on the way down. Try the hikes out of the Summit Lake trailhead down toward Snag Lake and/or up to Cinder Cone through the painted desert for some cool volcanic views. Cinder Cone is accessible from Butte Lake I think also (that is probably the closest trailhead.)
I used to live in Southern California (now in Nor Cal). There are lots of great hikes in So Cal. Places for you to check out: Mt. San Gorgonio area of San Bernardino Mountains, Mt. San Jacinto area, San Gabriel Mountains (Angeles National Forest) - lots of great day hikes plus some pretty solid backpacks that can be more remote than you would expect so close to a metropolis, Joshua Tree (mostly day hikes, but I've done some backpacking there too), and best of all is that you are not that far from the South Eastern High Sierra. Head up to Lone Pine and up to the Golden Trout Wilderness or points north for all the passes that access some of the most beautiful hiking I know.
Edit: I should mention that if you have not seen Redwoods and you are thinking of taking the coast for that experience, by all means go for it.