One possible scenario could be that Harry discovers a hidden magical passageway in his tiny bedroom at the Dursleys'. It could be a secret portal created by a well - meaning wizard long ago to help any oppressed magical being in the Muggle world. Harry stumbles upon it while looking for a lost sock or something mundane. Another scenario might be that a group of friendly magical creatures, like house - elves, conspire to help him escape. They create distractions around the Dursley house, like making the pots and pans fly around and creating chaos, which allows Harry to slip away unnoticed.
One possible plotline could be Harry discovering a hidden magical ability that helps him escape. For example, he might find out he can teleport short distances, which he uses to get away from the Dursleys' house when they are being particularly cruel. Another could be that he gets help from an unexpected magical creature that has been secretly observing him all along. Maybe a house - elf that takes pity on him and shows him a secret passage out of the house.
There could be a group of magical outcasts in Canada who take Harry in. These are people who have been shunned by the mainstream wizarding society for various reasons. They would understand Harry's need to escape and would protect him because they see him as one of their own, someone who is also trying to find a place where he can be safe and free.
Well, in this kind of fanfiction, Harry might meet some new magical creatures unique to Canada. Maybe he'll encounter a friendly Canadian werewolf who helps him hide from any threats sent by the Dursleys or Voldemort's followers.
One possible scenario could be that Harry uses his magic skills in a creative way to escape. Maybe he creates a diversion with a spell to distract the Dursleys and then slips away unnoticed. Another could be that he gets help from an unexpected ally, like a friendly magical creature that guides him out of the house.
The Dursleys are also important characters in this context. Their actions and attitudes towards Harry are what he is escaping from. Petunia's overbearing nature, Vernon's hostility, and Dudley's bullying could all be factors that drive Harry to find a way to leave. And there could be other minor characters from the wizarding world, like a friendly neighbor who is actually a retired wizard and gives Harry some crucial advice or a magical item to aid in his escape.
One way the Dursleys can be good in fanfiction is if they are forced to face the consequences of their actions early on. For instance, they might receive a warning from the wizarding world that if they don't treat Harry well, there will be serious repercussions. So they start to be nicer to him. They could provide him with a proper room, better food, and allow him to have friends over.
In some Harry Potter fanfictions, the Dursleys are depicted as nice. This could be a really interesting take. It might show how they could have been different if they hadn't been so influenced by their dislike for magic. Maybe they could have supported Harry more, or at least been less cruel. For example, a fanfiction could explore a scenario where Vernon Dursleys actually encourages Harry's academic achievements at school, instead of always putting him down.
There's a chance he meets some magical creatures that can talk in the American wilderness. For example, he might encounter a Sasquatch that has a deep understanding of the ancient magic in America. They could form an unlikely friendship and the Sasquatch could help Harry in his journey to adapt to the new magical environment.
It's possible that an old acquaintance from Hogwarts who has family ties in America could assist him. This person might already have a network in America and could introduce Harry to important people. Also, there could be some reclusive magical scholars in America who, out of curiosity about Harry's powers and his role in the UK, decide to help him. They could teach him new magical skills that are specific to the American wizarding world.