As a non-US citizen, what's wrong with recreation.gov?
It just didn't turn out very well. Difficult to navigate, bloated JavaScript interfaces, poor discoverability.
It works, and worse websites exist. But it feels like a buggy early-2010s web app, and serious outdoorsy types have bots snipe the best reservations as soon as the system opens for the season. It's hard on people who don't use a computer every day and just want to plan their family's vacations.
Lots to be said for considering where and on what devices your users will be interacting with your website.