I use citynav with basecamp for Mac. Yes it has dirt roads. You have to zoom to .2 mile to get the smaller ones to show on the map. I've ridden thousands of miles of dirt roads all over the west and never had one not show on citynav NA. I've even made my own tracks on basecamp and then transferred them to my GPS. Then I went out and rode the tracks and the roads were all where they should be.
I'd say the maps are better than google maps.