Hint Book
At the same time the SNES game was released in the US, a small strategy guide / hint book was published. It was officially available by sending a mail order for $5 to the publisher, with an order form that came with the SNES game box. It's smaller than typical strategy guides (about 6" by 8.5"), mostly text and black-and-white images from the game.
My copy has been damaged somewhat over the years, but it's still readable. Here's a scan of it.