Nambe Falls, New Mexico. I've explained the Falls part in my Post. It's within the Nambe Pueblo, which is modern Indian community but not with the Indian Reservation status. (Home of Brown). It's more than 8.25 Miles north of Sante Fe. Between 5,000 10,200. Obviously he could have done it in a day. The water is warm therefore it's New Mexico due to the heat. You will get cold by the time you go through the cave. He said part of the clues didn't exist when he was young. The falls were created by the nearby dam. The Falls has several tiny caverns along the way so it may not necessary be behind the actual water fall but all the criteria will still fit. It's a place that means a lot to him. So much so, that he moved his entire family to Santa Fe. He's says fires might be threat. There were fires around the area a while back. He says you can see mountains and tress and animals from the location. Animals like lizards live in grottos. From the grotto's hole, you can see trees, mountains, and the blaze aka the sun. Here's an example of a grotto https://slm-assets3.secondlife.com/assets/1177962/view_large/c4566464aa9a80b3de329fb7746db305.jpg?1277201570 Finally, look at the map from Too Far To Walk. This map only contains places of relevance and intentionally leaves out other major towns and geography. Look at the where "Santa Fe is written. You see the blue line going through the N? That's the river where the Falls is located.

Good luck