ya, i know the viaduct road, not sure about the wildbill area, is that local to you?
It's out near Kila. Head up Truman Creek road up until Truman Saddle (some people take this road called Patrick Creek Road, but you end up going about 15 miles farther cause you head out near Foys Lake). Head on up that way and the trail crosses the road. I'm not sure where it starts, but the trails comes out near Black Tail Mountain somewhere (couldn't drive the trail as I still haven't fixed my 4WD, LOL!).
I've been exploring the country a little, so I've been finding some cool trails. Went on one that ends up going up the back side of Big Mountain, then heading down to the slopes (had to actually go down a ski hill to get out of it, as the end of the trail ended on a CLOSED GATE [the head of the trail was open] and, again, no 4WD at the moment, so the hill I went down was a little steep). Not sure if I posted pics of that outing or not, but it wasn't that exciting. Just a back road that heads up to a cell tower on the top of Big Mountain. Cool views of the whole valley though (you can see the north end of Flathead Lake from up there).
LOL! I may be confusing the shit out of all the non Montana folks on here.
The OHV park is about 25 miles from my house. I put 90 miles on the truck today exploring. 60 of them just the travel time from my buddies house to the trail.