From your first link: Landowners who grant public access to their land for recreational use are immune from liability for injury that “arises out of the use of the land for recreational purposes.” ORS 105.682(1). “The activity of crossing a parcel of land, by itself, is not a recreational purpose.” Liberty v. State Dept. of Transportation, 342 Or 11, 21-22 (2006).
If your intent is to get to someplace where you can “recreate” then getting there should be part of your recreation. The above is just absurd.
It would seem to me that if you aren't using a recreational trial for recreational purposes, you would be trespassing.