Came through there last year with no problems.
There is a BR Park website, and it now mentions some restrictions due to enviromental issues.
Unfortunately, the dickheads on quads have forced the arm of the BR Park Authority.
So, there are routes now that encourage motorized tourists, the roads you can use are signed. The opposite to how it used to be, when signs told you not use routes.
There may be some local temporary military restrictions, again signed or with MP Rangers.
Rode through there a couple of weeks ago and picked up a map from the Information Centre.. I'm still in Spain, but PM me your email address and I'll scan you a copy next week, when I get home.
This applies to anyone else interested, of course
It's a fantastic place.. well worth going.
Went all around there on legal routes last year - the scenery is well worth it. If you look and ride sensibly, the police are fine, if you look /ride like a dick head, I get the impression they'll come down on you like a ton of bricks. Luckily we were just bimbling around enjoying ourselves!