It's not just "Concealed Carry". For years, people were forbidden to even possess a firearm in any National Park. Many folks who had guns unloaded and locked in the trunk, had their guns confiscated and not returned by the Park Service. Those who were camping or sleeping in tents at night, traveling in RV's, even riding through the park with a firearm in the vehicle, were forbidden to have any form of protection. So it's not just CCW. But all of those folks who had to travel on road trips can now have a gun in the car, without fear of arrest and confiscation. I confess that I violated that regulation a couple of times, when traveling with my family and stopped to see The Grand Canyon, Yellowstone and Mount Rushmore. I'll be damned if I was going to travel across the country, sleep in hotels in areas unknown to me, eat in restaurants in a city with a high crime rate and not be able to protect and defend my family, only because I was violating a regulation when my family wanted to stop and see the Grand Canyon.
I had vowed to NEVER visit another National Park, as long as this ban was imposed on me. I wrote letters to the Park Service, politicians and anyone that would listen. I even sent letters to travel agents, Triple A, and anyone else who booked, provided information or even suggested a National Park as a destination for fun, leisure and vacations.
So now if you are allowed by that state to have a firearm in the vehicle, or your CCW permit is recognized, you may have the gun as if you were in that state, and do not have to abandon your gun rights simply because you cross a line into a "National Park". Those National Parks that just happen to be owned, paid for, funded, maintained and staffed by the taxpaying citizen.