When Zoro docked he realized he was a bit ahead of the canon time line due to the speed of Ark Royal. He decided to hide on a roof and wait for the best time to intercede. He watched as everything happened on the adjacent rooftop the Buggy Pirates were having their party.
He jumped in and took down the pirates that were coming after Nami as she burnt her hands putting out the cannons fuse. He asks Luffy. "So who is the cute girl captain."
Luffy exclaimed, "Oh she is our new Navigator."
Nami didn't verbally deny what he said as she was to embarrassed because Zoro called her cute.
Buggy interrupted them, telling Zoro that if the pirates hunter was here for his head he had another thing coming. Zoro responded, "I'm a pirate now but I will still take your head." He immediately drew Hyorinmaru and lunged forward, chopping his head off. He proceeded to grab Buggy's head and ran back to the cannon. He heaved, flipping it over and told Nami to light it. Everyone was stunned with how fast it all happened.
After Nami lit the fuse, Zoro tossed buggy's head to her telling her. "Here hold on to this for now." He then ran over to Luffy's cage and picked it up onto his back. Nami didn't catch the severed head, not wanting to touch it. When Buggy's head hit the ground he yelled out, "Careful of my head!" Nami and Luffy were startled that he wasn't dead. Buggy noticing their surprise, started yelling about how he was a chop chop man and would never die to a sword. Being startled as she was about a talking head Nami stomped on it knocking him out.
Zoro now with the cage on his back, told Nami his head was worth 15,000,000 belly and they should bring it with them. Nami, no longer caring about it being a severed head, picked it up with belly signs in her eyes. Zoro knew that would work. They then ran for it as the cannon went off.
Zoro stopped and took a rest in front of the pet shop. He may not have a wound this time around but that cage was still heavy. During their run he didn't even notice that Nami had slipped away and right now was meeting backup with them. Just like in cannon she had the key to the cage with her and the dog ended up eating it.
Zoro decided to let canon play out for the most part for now. Nami needed to start to feel that they were good pirates and Luffy needed these early fights. So he let Luffy fight Beast Tamer Moji without him. When Nami went to sneak away to steal the Buggy pirate treasure she tossed the head to him first and asked him to hold on to it for now.
Buggy had woken up at this point. When his pirate crew showed up, Zoro was attacked by Acrobat Cabaji. He had to drop the head in order to fight with his 3 swords. This allowed Buggy to reassemble himself. Luffy and Buggy had their fight with Nami showing up in the middle with all of the loot. Zoro won his fight easily because he wasn't hurt this time. Finishing Cabaji with Onigiri.
It generally went down like in canon. After the fighting the townspeople showed up. Luffy being Luffy, told them that they're pirates and he's the one that knocked out the mayor. The townspeople chased them out of town. At the boats Nami finally realized that Zoro lost the head. She got mad at him, screaming that he owed her 15 million belly. Then as they were sailing off in both boats, she got even more mad when she realized Luffy left the 5 million belly worth of treasure for the mayor and townspeople.
Zoro started laughing and said. "Well at least we got us a cute navigator now."
She screamed back at him. "Ahhhh! Stupid pirates! I'm only your navigator until you both pay me back! And stop calling me cute!" she said the last with a small blush.
AN: I'm not at all happy how this chapter turned out. ADD sucks when you're trying to write. I tried to redo it like 4 times so I just went with this.
Also I'm generally sticking to canon until they get more of the crew together. I don't want MC changing too much at the beginning of the story. I want the original One Piece characters to develop mostly the same. It feels wrong to write out pretty much what already exists. I'm constantly debating with myself of what to cut out from canon and what to explain more. I feel like I'm rushing things so I can get to the point of my story where I have ideas to make larger changes. It's not like I can just say boom, they pick up Nami, they pick up Usopp, a few different things happen and they're in logtown… Sorry for the long rant.
Any suggestions on how to improve my writing style are appreciated. I can't promise I'll actually improve with any of your suggestions. But I'll try. Yall should have seen some of my papers I had to write for school, they were never a good grade.
Chapter TLDR: Orange Town arc goes mostly as canon. Zoro doesn't get stabbed. Nami is slightly more attached to the crew than canon so far. Zoro owes her 15 million belly.