From memory and talking with law enforcement, NF follows federal highway laws for all Forest Service Roads. So your vehicle or transportation needs to be legal for use on a federal highway… unless the roads or trails are marked as ORV. For the Mt.Baker-Snoqualmie the only option is Evan’s Creek to my knowledge. And, that is still open but basically inaccessible for most people due to the Fairfax bridge closure. Not sure about the other west side NF options.