Bottom line is if you have a pedal assist bike with a motor rated at 250 watts or less, then you are pretty much considered a bicycle in most, but not all places. For instance AZ signed into law that they are not a motor vehicle and have all the rights of a bicycle. BLM and most National parks do the same, but not all. You are good to go on roads I would guess anywhere, it’s just how much they are accepted off road which is opening up all over as long as it’s assist and 250 watt motor- the battery can be any size.
The key is you can ride farther and breeze the hills where you may not normally want to take a bike. I rode way back in Tonto in an area closed to off roading and got into some nice isolated back country via sand wash. No way you could ride that on a bike. My wife rides to tennis in the summer and doesn’t break a sweat. You can dial it back and peddle more or less. All configurable as you might expect.
Got ya.....sounds like a cool way to see a lot of the national parks.....as long as you don't get run over by a tour bus