Best Tools for National Parks
The useful development since this was written is that the parks themselves publish good software, which was not true in 2010.
Start with the park service, not an app store. The National Park Service's own app covers every US park in one place, with offline downloads per park, official trail data, closures, shuttle times and entrance details. It is free, it has no ads, and it is the only source that is correct about the things that change: road closures, permit rules and whether the shuttle is running.
The two things worth doing before you arrive:
- Check the reservation system, months ahead. This is the biggest practical change since 2010. Timed-entry reservations, permit lotteries and vehicle reservations now apply at many of the busiest parks in high season, and turning up without one is how people get turned round at the gate. The rules differ per park and change per year, which is exactly why the official source beats a blog post.
- Download the offline map. Cell coverage inside parks is patchily worse than the surrounding countryside, deliberately in some cases.
Then the third-party tools earn their place: AllTrails for recent trail conditions from people who walked it last week, Gaia GPS for anything off the maintained trails, and Stellarium because several of these parks are certified dark-sky places and the night is half of what you came for.
What has not changed: go early. The parking lot at the trailhead fills before nine in summer, and the difference between arriving at seven and arriving at ten is the difference between two different holidays.