Part 1: How Daryl Ended Up in France (Season 1)
The show begins with Daryl tied to an upside-down lifeboat, washing ashore in Marseille, France.
The Abduction
Before the show started, Daryl was in Maine (USA) trying to find fuel. He made a deal with a group to round up walkers in exchange for gas. However, he got into a fight with them, and they threw him onto a massive cargo ship heading for France. This ship was run by a group called Pouvoir des Vivants (Power of the Living). Daryl escaped the ship by blowing a hole in it, which is why he washed up on the beach.
The Mission: The "Messiah"
Daryl meets Sister Isabelle, a former thief turned nun, and a young boy named Laurent.
The Legend: The religious group "Union of Hope" believes Laurent is a savior destined to restart humanity.
The Science: Laurent's mother was bitten while she was in labor. She turned into a walker while giving birth to him. The Union believe this makes him special or even immune.
The Goal: Daryl agrees to escort them across France to a sanctuary called The Nest (Mont-Saint-Michel) in exchange for a way back to America.
Part 2: The Battle for France & Carol's Arrival (Season 2)
While Daryl is becoming a father figure to Laurent and a "Knight" for Isabelle, Carol is back in the US realizing Daryl never came home.
The Book of Carol
The Journey: Carol tracks Daryl's motorcycle to Maine. She meets a pilot named Ash who has a small plane. She manipulates him by lying, saying her daughter (Sophia) is alive in France and needs saving. They fly across the Atlantic.
The Conflict: France is torn between two factions:
Pouvoir: A paramilitary group led by Genet who experiments on walkers to create "Super-Walkers" (Variants).
The Union of Hope: Led by a man named Losang, who eventually turns out to be a fanatic willing to sacrifice Laurent in a "test of faith."
The Tragedy: Sister Isabelle is killed during a raid on The Nest. Daryl is devastated as she had become his primary romantic interest.
The Departure: Daryl and Carol reunite. They manage to get Laurent and Ash onto the plane to fly back to America, but there isn't enough room/fuel for Daryl and Carol. They stay behind to let the boy escape.
Part 3: The Path to Spain (Season 3)
After the plane leaves, Daryl and Carol are stuck in France. They decide to travel through the Chunnel (the underwater tunnel from France to England).
The London Stop: They emerge in London and encounter Julian Chamberlain. London is a "dead city"—almost no humans left.
The Shipwreck: They attempt to sail from England to find a way home, but a storm or conflict (the details of which lead into Season 3) causes them to shipwreck on the Costa Da Morte (Coast of Death) in Spain.
Daryl Dixon (Norman Reedus): Continues his journey across Europe after his time in France, now attempting to navigate Spain to find a way back home.
Carol Peletier (Melissa McBride): Having reunited with Daryl, she travels by his side as they face new threats in the Spanish landscape.
Antonio (Eduardo Noriega): A kind resident of Solaz del Mar (Solace of the Sea) who becomes a significant ally and potential romantic interest for Carol.
Federico "Fede" de Rivera (Óscar Jaenada): The mayor of Solaz del Mar, a thriving community in northern Spain.
Paz (Alexandra Masangkay): A "gitana cowboy" who serves as the head of security for the Solaz community.
Roberto (Hugo Arbués): Antonio's son who is in a relationship with Justina and hopes to escape their community's restrictive traditions.
Justina de Rivera (Candela Saitta): Federico's niece, caught up in a dangerous system where young women are traded for protection.
Guillermo Torres (Gonzalo Bouza): The leader of El Alcázar (The Fortress) in Seville, who claims descent from the Spanish monarchy.
Chofo (Vicente Romero): Leader of the Buzzards, a nomadic group of bandits who travel across Spain using walker-powered trains.
Amaia (Nansi Nsue): Leader of the Limbos, a community of survivors afflicted with leprosy living in harsh conditions.
Laia (Raquel Ferri): Leader of a refugee community in Barcelona composed of women who escaped from El Alcázar.
Jeffrey Grimes: While not appearing on-screen as a living character, Rick's brother is confirmed to have been in Barcelona at the start of the outbreak, bridging the show's story with the comic The Alien.
Julian Chamberlain (Stephen Merchant): A guest character Daryl and Carol encounter in London before arriving on the Spanish coast.
1. Walker Variants
France is "Ground Zero" for the virus, and the walkers are different there:
Burners: Their blood is acidic and burns skin on contact.
Ampers: Genetically modified by the French scientists to be faster, stronger, and more aggressive.
Hallucinogenic Walkers: In Season 3, they encounter walkers affected by environment/chemicals that cause people to see visions of their past (Carol sees Sophia).
2. The Spanish System (The "Ofrenda")
The list you have mentions The Fortress (El Alcázar) and Solaz del Mar. In your story, you should focus on the "lottery" system:
Communities like Solaz are protected by the "Monarchy" in Seville.
In exchange, they must give an Ofrenda (an offering), which is often young women who are essentially traded away. This is the central conflict between Daryl/Carol and the Spanish villains.
3. Transportation
Note the Buzzards on your list. They use walker-powered trains. This is a unique technological twist where walkers are used like literal engines to move massive nomadic groups across the Spanish plains.