I love visiting the National parks in California whenever I get the chance, and over the years, I've developed a seasonal plan:
In the spring (April/May), I go inland to Sequoia, Kings Canyon and Yosemite as that is when the snow is melting and the waterfalls are at their peak (by mid-summer the falls are often little more than a trickle)
So, In the summer, I hit the coastal sights Muir Woods, Avenue of the Giants, Hearst Castle, Napa Valley, Carmel, 17 Mile Drive etc.
That being said, Yosemite at this time of year is still a natural wonder and you have an opportunity for a drive that isn't possible in the snowy parts of the year... If Highway 120 and the Tioga pass is open now, I'd recommend the drive in through Tuolumne Meadows into Yosemite, or maybe on your way back out, I haven't done the drive for about 17 years, but from what I remember the views were spectacular (it's a long drive though, so if it doesn't fit into your route, don't add it on (Google street view does have all of this mapped, so you can always watch it on your computer to get the experience anyway) ... it does take you past Mono Lake - very erie - and can give you a chance to go through Death Valley then up through Lone Pine where a lot of westerns were filmed - you'll recognize the landscape instantly.
Make sure you get back to Yosemite in the spring to see the waterfalls though, you'll be glad you did.
As for Sequoia and Kings canyon, you have to visit General Sherman tree and the redwood groves, and visit Moro Rock - it's a bit of a climb, but the view is fantastic! http://www.travelblog.org/Nort...ark/blog-106878.html
Depending on how far north you go, the lava tubes in Lassen are kinda cool to walk through (bring a flashlight or rent one from the ranger station), but you're from Hawaii, so maybe they're not so exciting?
... you really can't go wrong at any of the parks or drives, and it sounds like you've got the perfect excuse to make the trip a few times per year.