The main characters are without a doubt George and Lennie. George is the more practical and cautious one. He plans for their future and tries to make sure they stay on track. Lennie is full of child - like innocence. His actions are often driven by his immediate desires, like touching soft things. In fan fiction, their relationship is usually explored further, showing how they interact with the world around them, with George constantly guiding Lennie through various situations.
One idea could be to explore what would happen if George and Lennie found a place where they could actually settle down without any trouble. They could start a small farm together, and Lennie could finally take care of all the soft animals he loves. Another plot could be set in a different time period, like modern day. How would they adapt to the new world with all its technology? Maybe Lennie would be fascinated by big machines and George would have to figure out how to keep him out of trouble.
One common theme is friendship. George and Lennie's relationship is often at the center, showing how they support and care for each other. Another theme is hope. Despite their difficult circumstances, fanfics often show them having hope for a better future.
Their friendship can be explored through flashbacks. Show moments from their past, like how they first met or a time when George saved Lennie from trouble. This would give readers a deeper understanding of why their bond is so strong.
One plot idea could be that George and Lennie find a hidden treasure on the ranch. They have to keep it a secret from the other workers who might be jealous and try to steal it. Another idea is that they rescue an injured animal on the ranch and nurse it back to health together. It shows their kind hearts.
One great George x Lennie fanfic is 'The Bond Beyond Words'. It really delves into the deep friendship between them. The author beautifully portrays how they rely on each other in a harsh world. Another one could be 'George and Lennie's New Beginnings' which takes a different spin on their story, showing what could have happened if they had found a more idyllic place to stay.
Since I haven't read it, it's hard to say for sure. But it could be a friend or a love interest. Maybe a person named Mary who has a crush on George and will do anything to save him from the hostage situation at the lake.
George Martin has a somewhat complex view on fan fiction. He generally seems to be more open - minded compared to some authors. He likely sees it as a form of flattery in a way, that his works are so loved that fans want to create their own stories within the world he has built.