First time in Dubois/Tog...

Honestly get there and blast off. Its easy to find huge play areas. That said everyone will find the easy ones and they get tracked up fast. We usually pack gas and blast trails couple/few days out of ten day stay. Eat at Tog, Brooks, Crooked Creek or Line Shack if open that day. Gas at Crooked if you get that far east.
IMHO
Best snow (least trail access), North side of 26 main road. Esp around and North of Brooks lake near Wilderness area. Be mindful of boundary.
Tonsa play areas easy to find everywhere south of 26. Trail CD is the Main. Always be mindful of its location on bad visibility days. You find CD you home free. Great riding between CD and E. If trail riding day E & F are pretty good for scenic views as is O if good snow and visibility. One day I plan to hit the south system, but Ive never been there when the far south stuff had snow enough making it worth checking out.

PS...If no fresh and groomers not active the trails will suck and beat $hit outa you...Best to plan trail days during the week...