When that link was first established it was very informative and easy to navigate and find places to stay on our travels. Now the link is saturated with advertisements and numerous pop-ups that get on my nerves long before I find something.
We like Indian casinos and have stayed in at least a couple dozen. They can be an exciting stop and some that started out as being free have added water & elect and dump stations with around the clock security by reservation police.
When we suspect their might be a casino RV Park in our planned travels we power-up a search engine and ask the state about Indian casinos. Once while in up state NY we found a nicely appointed smallish Indian casino real close to the St Lawrence river and the bridge to Canada. It provided free paved
dry RV parking, real close to the casino.
A little while ago after reading your post I found the link to that casino as it is today. The links are active.
https://mohawkcasino.com/accommodations/rv-park/
https://mohawkcasino.com/