Planning a road trip from Texas to California

I am an au pair from Norway working in Austin. This summer, some friends of mine from Norway will come over for probably 2 weeks, and we plan to go on a roadtrip. We'll start in Dallas, Austin, Houston or San Antonio, and go west, through New Mexico, up to Colorado, then Utah, Nevada and California.
Is that too long of a route for 2 weeks? We want to do more than just sitting in the car all day, and would love to do stuff like canyoneering, rafting, mountain climbing, hiking, swimming, and so on.
Places we want to see is Grand Canyon, Badland Caverns, Las Vegas, maybe Roswell...?, Rocky Mountains, Death valley. Any other places that are worth visiting? Any of the mentioned places that are NOT worth visiting?

And how should we do it with the car? Should we rent, or buy a cheap car and sell it when we get to California? One thing I consider is buying/renting a van, so some of us can sleep some nights in that + a tent, so we don't have to sleep at motels every night.

Anybody has any tips and help for me on how to plan this trip?

Quoting audunk

I am an au pair from Norway working in Austin. This summer, some friends of mine from Norway will come over for probably 2 weeks, and we plan to go on a roadtrip. We'll start in Dallas, Austin, Houston or San Antonio, and go west, through New Mexico, up to Colorado, then Utah, Nevada and California.
Is that too long of a route for 2 weeks? We want to do more than just sitting in the car all day, and would love to do stuff like canyoneering, rafting, mountain climbing, hiking, swimming, and so on.
Places we want to see is Grand Canyon, Badland Caverns, Las Vegas, maybe Roswell...?, Rocky Mountains, Death valley. Any other places that are worth visiting? Any of the mentioned places that are NOT worth visiting?

Anybody has any tips and help for me on how to plan this trip?

If you want to do more than sit in a car, I believe you are over reaching a bit. Suggest you narrow down your focus.
Leaving Texas, head towards Carlsbad Caverns (not far from El Paso). Easy drive to Santa Fe/Taos areas of New Mexico which is quite scenic. From there, on to Colorado. Go west to Zion National Park in Utah. Drop down to Las Vegas, Nevada (you will only need one day there). Depart south to Arizona (on the way, stop at Hoover Dam and look at that engineering marvel). Once you take in the Grand Canyon, look at your schedule. Chances are you will be ready to head back to Texas and best save California for another excursion.

Good luck and have a great trip.

You can drive direct Texas to California in two solid days. So there are an extra 12 days to fit all kinds of stuff in. You can do many of the things you want to do inside that time, if you budget your time well. And, since you're young, you'll be able to solidly cover many of the htings. a couple of times a day. Two weeks, Texas to California? Easy!!

D