At First Glance: Too Much
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Taking your itinerary at face value, you've got a minimum of four solid days of driving, and that's before yo account for the slower pace of an RV. When you factor in crossing and re-crossing the Sierra Nevada and the speed limits in national parks, as well as the extra time to stow everything in the RV for travel every morning, it will end up being more like five. I'm also assuming that there will be a day's worth of flying at either end, and that those days will include picking up and dropping off the RV with all the equipment checks and paper work that that entails. So, of your 14 days you're left with seven to actually see and experience stuff. A full day in San Francisco and Los Angeles (in addition to the aforementioned travel work) leaves you five for everything else and that's simply not enough for Yosemite, Sequoia, Death Valley, Las Vegas and the Grand Canyon let alone Tahoe and everything else in between. Something's got to give if you want to actually spend some relaxing time at any of the places on your list. Personally, I would lean towards dropping Las Vegas, Hoover Dam, the Grand Canyon and Los Angeles, concentrating on northern California and returning to San Francisco.
AZBuck