Well, it could be about Harry and his friends discovering a magical place where time stands still and they can have an eternal vacation. They might encounter new magical creatures and learn spells that are only available in that special place.
Well, Harry Potter would be at the center. But in addition to his usual friends, some other characters could be main characters as well. For example, Neville Longbottom. He has grown a lot in the original series. In this fanfiction, he could bring his knowledge of herbology to the immortal vacation, maybe using plants in the new vacation place in ways no one has thought of before. Also, Dobby the house - elf could be a main character, as his loyalty and magic could play a big role in the adventures during the vacation.
Harry might encounter some magical nomads. These are wizards and witches who don't settle in one place but travel around the wizarding world. They could introduce Harry to different cultures within the wizarding community and show him some unique magic that he has never seen before.
One common theme is discovery. Harry and his friends often discover new places in the wizarding world during their vacations. Another theme is friendship. Their relationships are strengthened as they go through different adventures together. And there's also the theme of magic outside of Hogwarts. We get to see different types of magic being used in various vacation settings.
I'm not sure specifically as I haven't read this particular fanfiction. But generally, in a Harry Potter fanfic, a 'forced vacation' could be about a character being made to take a break from their normal wizarding life. Maybe Harry is forced to go on a vacation away from Hogwarts due to some plot device like security reasons or a magical decree.
Well, perhaps Harry would go to a wizarding beach where he could practice magic without the usual Hogwarts restrictions. He might meet some new magical creatures that are only found near the sea.
In many Harry Potter summer vacation fanfictions, Sirius Black is also a character that shows up. Given his relationship with Harry and his status as a wrongly - accused wizard. He could be involved in protecting Harry during the summer or helping him with some secrets about his family. Luna Lovegood might also be included, with her unique perspective on magic and the wizarding world, she could add an interesting element to the summer vacation stories.
Well, perhaps Harry and his friends could visit the famous Vegas shows. They might be amazed by the magic tricks there, thinking they're similar to the spells they know. And they could explore the glittering casinos, but of course, not for gambling in a proper 'Harry Potter' way. Maybe Hermione would be interested in the libraries in Vegas, if there are any special ones.
It's hard to say. Some fanfictions gain a lot of popularity within the fan community, while others remain relatively unknown. If it has a really engaging plot, unique characters, or great writing, it could be popular.
One great 'Harry Potter vacation fanfiction' is 'Harry Potter's Summer Adventure'. It takes Harry on a magical journey during the summer break, exploring new magical places outside of Hogwarts. Another one could be 'Vacation with the Weasleys', which focuses on Harry spending his holidays with the Weasley family and all the fun and chaos that ensues. And there's also 'Harry's Overseas Vacation', where he travels to a different wizarding country during the vacation and discovers new spells and cultures.