Forget about a bike trail along the railroad next to highway 58 to Oakridge. That track is the very busy mainline for Union Pacific and also serves Amtrak, no way will they allow recreation near that track. There is a road along the other side of Lookout Point Lake that goes from Lowell to West Fir, mostly dirt, but well packed (mostly). Chances of getting that paved are slim, but better odds than a rails and trails.

With wider shoulders in 126 it would get a lot better use up the McKenzie River.