I'll be flying to the Urals and start my road trip in Chaykovskiy, driving through cities like Kazan and Nizhny Novgorod and back to Moscow. Do you have any general tips for a road trip in Russia, or any specific sites to see in those cities and along the way?
Do you speak Russian? As already mentioned, it may be difficult to find someone speaking English in some rural areas of Russia... but then on the other hand people are really helpful! As for safety, I wouldn't freak out too much. Sure, you have to be cautious, but don't let it separate yourself from the people because you only choose touristy English-speaking places on the main streets etc...
Oh and perhaps you could also make a stop in Vladimir just before getting to Moscow.
Travel with a companion, preferably a Russian.
Plan in advance safe places where you will sleep and rest.
Do not expect a lot of English speakers.