Butler maps are mostly for pavement. They use different colored lines for different types of routes though, and not all of them are paved.
Looking on Butler's website the G1 series maps say they also list the best dual sport routes. My guess is the routes will be laid out by color. In the online version of Butler Maps that I use, dual sport routes are purple, and G1-G3 routes are yellow, red, and orange. I'm sure the paper map is similar.
One of the people who helped create Butler Maps also created the app REVER (
www.rever.co) and the Pro version of that app has all the Butler maps available, but of course it is an app, not a paper map. It is handy though because you can turn on and off the different routes, so if you only want to see dual sport trails, you can turn the others off and have a less cluttered look.
As for the BDR, it is geared toward dual sport and adventure motorcycles, so if Butler and BDR have teamed up, those might be the maps you would want. They probably only highlight the actual BDR though, and not other trails that might be in the G1 map.
The TAT is also a dual sport route, with some paved roads when necessary. The biggest problem with the TAT used to be that the gps tracks only worked from east to west. I don't know if that is still the case.
These routes are supposed to be passable by an adv bike. I know some sections can be hard, and weather can change a road from moderate to extremely difficult in a short time, especially in the desert or any high country. You can watch videos on Youtube with each of the BDR's or buy the DVD (the Northern California route was just released. I don't know if they have a video yet).
The is also an app called OnX Off Road that people will post trail updates on. Sometimes they are recent, sometimes they are months old, sometimes there are none. It lists a HUGE amount of trails and routes in the US though.
-John