I drive all 48 states, although I am listed within the company as a "regional" driver.
Our company provides routing. But I typically route myself. We are not required to follow the routing, unless our out of route is WAY out of route.
I use 3 different versions of mapping software to assist. One of which has a GPS attached to the laptop. Even then, I have to modify it to suit my needs. Some roads are not accessible, some roads are, but not shown as a truck route.