Walt Disney's Goofy and the Miller
I dont think I'm giving too much away when I reveal that in this Disney storybook, certain parties "lived happily ever after".
The old miller of the title runs a watermill, and Goofy is one of the three miller's helpers, though he's the only one that isn't lazy. The miller is getting ready to retire, and vows to give the mill to the helper who best completes a challenge he sets.
... and to tell you much more would ruin the surprise!
The story was originally published in Denmark as Fedtmule og Mølleren der Ville Ha'en Hest, and the English language version in its Wonderful World of Reading series was published in 1978. It's colourful pages make it suitable for reading to young children, or older ones can read it themselves - it's arould 1000 words long. The title page shows a fairytale world with the watermill, castles, and even a windmill, and the mill machinery illustrated later is likewise from the realms of fantasy.
Walt Disney's Goofy and the Miller, Grolier Enterprises Inc, 1978, ISBN 0-7172-8477-8. Also available in various Random House editions.