One of the best and most diverse national parks in the United States. From mountains, to waterfalls, to rain forests, to the ocean! The beauty of this park is unreal. I recommend taking your time exploring because there are a ton of great trails and views scattered throughout the different areas. We spent 2 days here and saw most of the popular attractions. You could easily spend 3 days though. Make sure to map out your trip as the entire park is huge. There’s not a lot of cell service, so I suggest downloading Google Maps beforehand. September is a great time to visit! It’s not as crowded as the summer months, but you still have a chance for sun and warmer temperatures.