Near Vegas, we don't have an official national park. But Red Rock Canyon NCA is treated much like a national Park (But is operated by BLM). The rangers are making enough of a show to give one the impression the area is closed; but are being pretty even-handed for locals. The gated scenic loop is closed, and tickets are issued for people who cross the gates (which have clear warnings). But just a mile or two south on route 159, are several trailheads with parking areas maintained by the county, and there are trailheads with unmaintained parking in Calico, at the east end of RRCNCA. The unmaintained THs and parking have been drawing lots of folks, and there has been no effort to issue tickets or close off the parking. Hundreds of people hike from those "open" THs each day during the closure.
This is the Dept. of Interior policy:
http://www.doi.gov/shutdown/fy2014/upload/BLM-FAQ.pdf"Will I be able to visit BLM-managed public lands?
All recreation facilities, including campgrounds, boat ramps etc., will be closed. If it is a nondeveloped
recreational destination with no controlled access, you may visit. However, there will
be no services and there will no non-emergency services available."There is some interpretation as to "non-maintained" and "controlled access." West of Hayford Peak, on BLM land, a plastic Barrier was erected on the Deadman Canyon dirt road. The lower part of that road was bladed in 2005, so perhaps it is viewed as "maintained," and perhaps the new plastic barrier is "control."