Just letting you know, I did talk with the Ranger Station a couple of years ago to get an explanation of the stickers and such. They told me the Special Service use Sam Houston Nat Forest Sticker is only for NON-STREET LEGAL vehicles, like 4 wheelers and side by sides, so you don't get tickets using the roads inside the park. They said that if you already have a street legal bike or vehicle, that NO STICKERS are needed other than the normal State of Texas stickers. So from what I gather, the Street Legal roads inside the National Forest have a special non-street legal exemption. I guess you cannot be ticketed for being on a non street legal machine on their roads, and that probably doesn't apply to State highways that cut through. I am sure you are legal to cross a State Highway with any non-street legal machine can cross a road, just not use the road.