It's not at all too much for 2 weeks, even without rushing. I've done a couple trips from St. Louis out to CA this way.
You're asking the right question, IMHO. Make a list of the must-see locations, and fill in with stuff you happen by.
I have two sons and did one trip with each like this. Tent-camp a day or two, motel stays on the nights in between. We did big loops, one clockwise, the other counterclockwise. On one trip we went to Wall Drug, Devil's Tower, Snake River, Crater Lake, redwoods, Yosemite, Meteor Crater, and the Oklahoma City memorial. We definitely did not spend enough time at Yosemite, so that part I would consider "too rushed."
About redwoods - everybody who can should see these at least once in their lives. There's no way to really appreciate how massive they really are without standing under them. Here are some ways that we've enjoyed them: 1) Camped among them in the Jedediah Smith State Park, 2) Drive down the coast from Crescent City, always picking the road that keeps you closest to the coast. It becomes gravel road for a while, but is two-lane for the most part. There's even some old structures that housed a WWII radar installation, disguised as farm buildings, 3) see the General Sherman Tree if you can.
It sounds like a lot for two weeks, but we did all that and more at a relaxed pace, sleeping late in the more, and still took less than two weeks. Tent-camping makes things easier than RV'ing, in the sense that campgrounds almost always have room for one more tent, but will have a fixed number of slots for an RV. Plus, it's cheap. We had a blast.
Also, when we went through Oregon we were warned at the Visitor Center about their law about filling stations. At the time, I believe it was about a $10,000 fine if you pump your own gas.
Hoover's Dam and Grand Canyon are other sights to see along the way.