many (most?) Suites hotels have two bedroom suites. Using Google maps, you can easily find those hotels near national parks and then just check their website
Check every website is not the answer I was looking for.
That's a pretty tedious way to search for hotels in the 21st century.
And IME recently I called so many hotels that I was about to book with points, and the
vast majority either claimed they didn't have any 2br suites (although the word "suite" is often in their brand name) or claimed that I'd have to pay for an upgrade (if it was available).
This was with IHG (platinum) and Marriott (gold).
BH the kids were usually tired so the 1br's were mostly survivable.
If only there was a hotel search engine which offered a search option for 2br suites.