RS 2477 is a simple and straightforward law. : “The right-of-way for the construction of highways across public lands not reserved for public purposes is hereby granted.”
2. Congress specifically and clearly reaffirmed the validity and intent of RS 2477 in 1976. Because RS 2477 became law in 1866, anti-access extremists argue that it is now somehow inconsistent with modern public land management policy. But just 22 years ago, when Congress repealed RS 2477 and replaced it and many other laws with the Federal Land Policy and Management Act, it specifically and explicitly reaffirmed all RS 2477 grants previously made.
http://www.icmj.com/more_page.php?id=5&keywords=RS_2477_Roads_&_Rights-of-Way_(Summary)
When the feds close roads on public land, irrespective of RS 2477 or county land use plans, more roadless areas are formed, thus more wilderness designation. It is a back door attempt to take more land out of use.