Well, the back story of Happy Valley could be related to the local area it's situated in. Perhaps it was built on land that had some historical significance, like an old farm or a natural gathering place for the community. Over time, it evolved into a full - fledged entertainment complex. They could have added rides, shows, and attractions based on the needs and desires of the local population and tourists alike. So, it's a combination of historical context, community influence, and the vision of its creators.
One idea could be exploring the backstories of the minor characters in Happy Valley in more depth. For example, the life of a local shopkeeper and how they interact with the main characters during the events of the show.
Catherine Cawood is a very popular choice. Her strong personality and the complex situations she faces in the show make her an interesting character to explore further in fanfiction. Writers can delve into her past traumas and how she overcomes them.
Definitely Catherine Cawood from Happy Valley. Her strong - willed and no - nonsense personality would be really interesting in the Twilight universe. And from Twilight, Edward could be a key character. His brooding nature and vampiric abilities would create an interesting dynamic with Catherine. Also, Bella could be included as she might learn a thing or two from Catherine about being independent.
A great plot for Happy Valley Twilight fanfiction could be a love story. Imagine a character from Happy Valley falling in love with a Twilight vampire or werewolf. There would be so many obstacles, like the different worlds they come from and the secrets they have to keep. The cultural shock between the two fictional settings would also add a lot of depth and interesting scenarios to the story.