I purchased the Delorme Street Atlas and GPS before I started truckin' in 1998, so I have never been in a truck without moving map with GPS capability. I can only imagine how much more difficult it would be without this great mapping assistance. I go to NY and NJ a lot, and it certainly is nice when the freeways jam up to be able to find an alternative route quickly and easily (like near the GWB). Also, if you make a wrong turn, or if construction or heavy traffic are a problem, you can command the program to take you to your destination from where you are now.
Street Atlas only covers the US, so if you are going to Canada you will also need the Map n' Go, which does cover Canada and the US, but not as detailed.
The DeLorme Street Atlas and GPS can be purchased at most major electronic retailers, like Best Buy. The last time I checked, the combo package was about $150.
Because DeLorme is not designed for truckers, you will have rare ocassions when the program wants to send you on restricted roads, or under low bridges. However, the assistance offered by the map program and GPS is 98% - 99% good.