Alternate Route to Graham Guard Station??

I know there must be a reason, but has anyone tried to get to Graham GS from the south/southwest area.  In particular on Benchmark there looks like two trails that will get there.  One from Deer Park Guard Station to Johnson Creek Campground and another just below it following Horse Haven Creek to same Johnson Campground.  My old topo software shows the Horse Haven trail, but not the other one.

Maybe they are hiker only routes??  Or are they Level 5+ type trails not suitable for DualSport bikes?

I don't want to waste time riding to these if they are not open to bikes.

Thanks for any feedback,

Jim