Seems like the overall advice is good. Two main points stick out to me... Stick to one half of the state(N or S), you will spend less time on the road. Even though Cali driving can be epic in the right car. Also, Cali boating is on another level, especially at higher flows.
The beauty of the far North boating like the Trinity, Cal Salmon, and Scott is they are all within an hour drive of one another. The Smith is a little further, but having the redwoods makes it a gem of its own... They all remain runnable into relatively low flows, and are all classic pool drop runs with the exception of a few rapids, but those can all be scouted or walked. The Tuolumne is a great run to combo with a Yosemite visit, but it gets beefy in a hurry during spring flows. The N. Fork American @ 2k or the Merced @ 4k are the only other reasons to go into the Yosemite drainage without seeing Yosemite, but that is just my opinion.
The Cal salmon also has the best kayaking schools on the Planet(fact), Otter Bar Lodge Kayak School. They are a great source of local knowledge and always have a good selection of quality used boats. California Kayak School Shop | Call 530-462-4772 | Otter Bar Lodge Kayak School