mixed habitat & densely vegetated hiding places

In this children's novel, American teenager Steve Duncan travels to an uninhabited Caribbean island with a family friend who is an amateur archaeologist, ostensibly to help search for evidence that the island was used as a base by the Spanish in the 16th century and that the feral horses there are descended from horses abandoned by the Conquistadors. But Steve has an ulterior motive: as a young child, he had a vision of an island just like this one where he would find a magnificent red stallion that would become his best friend. Could this island be the place where his dream comes true? (No points for guessing yes!)

I definitely read this around the same time I read The Tombs of Atuan as a kid. Both books involve getting lost in a pitch-dark underground labyrinth, and my memory mashed up the most compelling aspects of each until I couldn't remember which parts came from where. In this book, the protagonists find an extensive network of subterranean tunnels that lead to a hidden valley where the dream horse lives, but their flashlight breaks and they get lost. Upon rereading, I was shocked to learn that they're only lost for one chapter before they find their way out! I thought it lasted so much longer!! I vividly remembered some of the descriptions of the underground peril (especially where they're running their hands along the tunnel walls for so long that it rubs their skin raw) and I always think those details are in Tombs, but they're not. There's also a scene of finding human skeletal remains that I had confused with the dying prisoners in Tombs in my head.

It's funny that I would conflate these two books because aside from that one plot element, they're nothing alike. Farley put so much of his id into his books, and his bulletproof narrative kink was basically "what if there was an extremely majestic and special wild horse that no one could tame, but then I met the horse and we had a profound mystical bond!!!" In that sense, this is essentially the same book as his better-known novel The Black Stallion, it just uses a different setup to get to the unabashed id vortex in the middle where the boy and the horse develop their mystical bond and overcome life-threatening peril, which is the part that Farley really cared about. As a kid I was definitely not complaining about him retreading the same tropes, and as an adult I totally respect it. Good for you, Walter, out there writing dozens of self-indulgent books about befriending improbably majestic horses, living your best life.