I was just down there for a run the day before yesterday. The trail 'Hogsback' had a width restriction of 76 or 78". I had no problem in my toyota mini (76"ish), but a pair of 80 series land cruisers got scraped up going through the filters. Most of the trails dont have a maximum width restriction.
But we did run into the head forest service guy who is in charge of the trails and had a good long chat with him. He was intrested in making alot of the trails harder down there now. He had just finished working on alot of the filters and rock gardens making them more challenging.
He did also want to let us know that you MUST stay on the designated trail. They spent alot of time blocking off all the bypasses less capable rigs made from the winter. The more time he spends cleaning up garbage and blocking bypasses, the less time he has to spend on makeing new obsticles and new trails.:beer: