That is the only "legal" way to do it. However, if you are within 5 miles of an airport you will be restricted by the software. Many official parking areas are also near airports who fly tourists over the parks. I will note that in April/May this year we visited almost every state and national park in Nevada, Arizona, New Mexico, Utah, and Colorado and I never saw a single ranger ever (other than taking money at the gates). I did see many people flying drones and no one was complaining about it. I think the NPS has had a severe cut to their funding and have reduced staffing to nearly zero. I did run into several volunteer rangers (BLM types) but they were focused on controlling numbers of people into remote areas and were staying in the parking areas. So, at this point it is a matter of enforcement and compliance. Obviously, law abiding citizens will obey the rules no matter what, others are more flexible and will obey if they think they will get caught, and some will disobey no matter what and enjoy running the risk. What I saw was a majority of the latter, particularly motorcycles gang types flying pretty much anywhere they wanted obviously flaunting any rules, but they probably would never get challenged anyway. It would require a fairly large response force to deal with a group of bikers and I just don't see the manpower available to deal with something relatively trivial like flying a Mavic. Maybe in other parks there is more manpower. But what I saw everywhere I went was a dearth of it. This is true even in the private parks run by the native Americans.
Sadly, what I was seeing, and this is far worse than flying drones (which I personally disagree with the ban), were people destroying property, hiking in forbidden areas, destroying vegetation, etc. So, the US government is having a huge problem dealing with managing the parks at all. Maybe they are counting on the citizens to control it themselves?
With the UAS rules in a state of flux it is hard to determine what the definitions are and how they apply to the other federal and state agencies. The restriction put in place by the NPS restricts take-offs and landings for all aircraft inside park boundaries. How you define an aircraft is where the issues will lie. I had purchased a Zerotech Dobby which at 190 grams is below the legal definition of a UAS as defined by the FAA but has (sort of) 4K capabilities. I didn't even bother to bring my Phantom 4 to the US but regret that decision as I could have flown it pretty much everywhere without any problems. I also brought a Kite Aerial Photography rig which is perfectly legal anywhere (so far). I have that for when the winds are too excessive for flying a UAS like the Phantom 4. But, no one was there to ever check so I was disappointed to not have to defend any challenges (for my Dobby or for the kite). One of our group bought a DJI Mavic Pro and that was flown everywhere we went without any issues ever. They live outside the US so later enforcement is a non-starter say based on a published photo or video.
I fail to understand the logic being applied to UAS ban in parks. Take the Grand Canyon National Park as an example. There are a plethora of aircraft overflying the canyon roughly 1 every minute at relatively low altitudes. I saw quite a few animals such as elk and they are immune to the presence of humans or aircraft. You can literally go up and pet them if you wanted to. The noise of thousands of humans running amok and all these large aircraft and helicopters is far more of a noise hazard than a UAS is and clearly the animals have gotten used to it. But, the Grand Canyon is huge and the areas where people are allowed are really very small so maybe they are sacrificing a small area to save the larger area? We all know that after 100 meters you can't see or hear a Phantom or Mavic at all so I don't see the logic here. Impact from altitude might be more of a concern or like happened in Yellowstone some guy crashed his drone in a geyser. But, a different guy fell in drowned and was dissolved overnight so again the logic is weak.
I had the pleasure or working one summer, before being drafted into the Army, at Mammoth Hot Springs in Yellowstone. Every day we all went out and fished out litter from the hot springs and pools tossed in by the tourists. So, this is an ongoing problem of pollution and I just don't see the need to specifically restrict one group of tourists who generally are safe. Obviously, the same restricted tourists by their actions are telling the US government what they think of the ban. Personally, I obeyed it but I did get some great shots using my kite. The Dobby is more or less useless as it has a range of 100 meters a 9 minute flight time (actually a lot less after calibrating the compass) and cannot fly in any significant wind at all. But, it is great as a selfie drone for short distance shots and does fit in your pocket. I did use it to fly in slot canyons way out in the off road regions not in parks.
Maybe things will change as this hobby becomes mainstream.