Okay... having done this semi-recently (about a year ago) with a moving van, my first suggestion is: skip Nebraska.

The way I came down was I-80 -> I-76 -> I-15 -> LA. That route takes you through Vegas on the way down, and since you're going to be driving back to Vegas later, you might not be so keen to do that.

If you don't mind a bit of a northward detour, you could hop up to I-90, and hit Mt. Rushmore, in S. Dakota. From there, you can take some non-freeways to Wyoming, and see Old Faithful, in Yellowstone. Going south from there on the 89, you can hook back up with the I-15 above Salt Lake City. You can make a stop in there to visit the Mormon Temple. You can then either follow I-15 all the way down, or jump on I-80 through Nevda to Reno. I haven't been to Reno, but I've been up in the Sierras there, and they're very nice (though not as nice as the Canadian Rockies, IMHO). Of course, from there, it's San Francisco, and, going south, you can see some Redwoods in Santa Cruz before following the coastal highway down to LA.

The only other slightly more interesting route I can suggest is to head down I-55 to St. Louis to take a gander at the Arch, then just head west on I-70 through Denver. Following the I-70 through the Colorado Rockies is a very nice drive -- do it in the daylight. You'll pass by Vail, and all those other nice ski resorts. When you get into Utah, you could detour through the southern end, which has a number of drop dead gorgeous national parks. Then, of course, you're back on the I-15 to LA.

I've done all of the first route, most of the second route (I haven't done the Sacramento -> Reno -> SLC stretch), and chunks of the third. I think the second route is the more interesting, but it definately takes longer.

I haven't tried going down to the I-40, and taking the southern route, so I can't give any recommendations there. There's a couple guys at work that have done it (from S. Carolina), and say it's not that interesting, but I'll check it out for mysolf one of these days. Since you're car camping, you might want to try the southern route, since it's still snowing at the higher elevations. Mammoth got 4' last week, and the Grand Canyon got snow, as well.

On the way back, you might want to stop in at the Hoover Dam, and the Grand Canyon, which are both reasonably close to Vegas. Either way, I recommend not going home the same way you drove down.

Don't forget your Empeg. When I moved down, I had an FM radio and one working speaker.

Cheers,