okay, so I just got the scoop from the whatcom county's sheriff's office.
Officer Turner is the person who runs the FS patrol. He goes out up here if DNR, FS, or private forestry requests them.
1) Do NOT go past a gate, open or closed unless it specifically states motorized vehciles can be there. ALL Sierra Pacific land will state that no Motorized vehicles are allowed. Hiking is allowed on Sierra Pacific land, but only on the road, no off-trail.
2) A gate is like a front door to a house. Don't go beyond it unless you have permission or the sign says specifically so. Otherwise you can get cited for trespassing.
3) DNR land is open for hiking all around, unless you're causing damage to timber.
4) DNR land is CLOSED for motorized access unless it says specifically so. Walker Valley is the only place 'trails' are open for, everything else is illegal
5) Johnson Security runs patrols on Sierra Pacific land, and if you subject to being detained if you beyond a gate. If there is no gate, they will give you a written warning. Suggestion: Don't come back and get caught again.
6) It is malicious mischief to be off trail.
6a) However, if its an established trail, you'll likely get a warning, not a ticket. Turner told me they're pretty good about using good judgement between 'I didn't know' and 'trail blazer'
6b) if you're found to be blazing trail, you'll get cited.
7) In -most cases- you will not get your vehicle impounded by the Whatcom County sheriff's department. He said its rare for this to occur, depends on the situation though.
8) His quote: "If you're out camping and go down an old abandoned raod, that looks well established but technically illegal, you'll probably not get contacted." Key is to use good judgement.
A very personable guy. Brings to light a few things. Another thing he brought up was 'contact' and 'prosecution'. There are standards (what I've listed above) on which you might get contacted, and prosecution which would be the ones to take you to court. Its up to them to decide if you've passed the grey area of using open forest land or not. The officer will try to use best judgement and will usually only make contact if he thinks its something obviously out of the norm.