Hawkmoon gave the pertinent info on National Parks and state laws. I carried all over Yellowstone and Grand Tetons. I carried concealed, but open carry is allowed. I never did because there are so many people from so many countries, I didn't want to take a chance of a hoplophobe panicking. Gun was locked in the car when I entered a building. I recommend renewing your CCW. It will be good everywhere you mentioned except of course, CA. Also I believe you need a "resident" permit from your home state for CO - if you're from WA but carry a UT permit, that's a no-go in CO.
For Yosemite and Sequoia, and CA in general, your gun is going to be unloaded in a locked container while traveling. The "locked container" can be pretty much anything, even a rucksack. You can keep the unloaded gun and ammo in the same container. Hence, a semi-auto is probably best since you can keep the loaded magazine and gun together and I would think making the gun operable is faster this way than a revolver, even with a speed loader.
I always carried a small steel pistol case that has a steel cable to secure it under a seat. I used the combo style, and always kept the combo one number off of "open" (e.g., combo =123, I kept it at 124). This is really only "smash and grab" protection, but hidden under other stuff, it works.
On the trip, if you need any ideas for cool hikes or stuff to see in the CA National Parks or the Eastern Sierra, PM me when you have a schedule, and I can give you some neat day hikes and sights to see.