My experience is it isn't really. I used the web version to plan a trip across Mojave National Preserve once, and it came up with a totally innocent looking rou

My experience is it isn't really. I used the web version to plan a trip across Mojave National Preserve once, and it came up with a totally innocent looking route using some unpaved roads, which was supposedly faster than going around using the I40 and route 95. The road was ok for the first few miles but anything over 30MPH would be asking for trouble, and not even nearly halfway in I had to turn around because the road was so bad a 2WD would definitely get stuck eventually. The longer route using freeways would have added 30 minutes to the 2:30 hour trip time according to Google, but in reality continuing on the dirt road would have taken at least 4 hours at the speed I was able to go, if I had even made it.