Be very careful on Mountain Pass on I-15 when you get into California. That drive can be dangerous and the people are crazy. Also watch your speeds going across the desert. You'll be going faster than you realize.
A neat little detour is in Goodsprings outside of Vegas. I accidentally stumbled into the Pioneer Saloon back in 2003 on my way back across the country because I wanted to wait until night time to go through Vegas and see the lights. Really cool old western bar that has had a few movies shot there.