Toads in Paper Mario: The Origami King are folded all over the game. Some are a bit more hidden than others, but it's up to you as Mario to save them all. A handful of them are merchants and traders from Toad Town and other stores. If you want to use the ship in Toad Town, you need to find the Sea Captain who has also been tucked away. You will be able to save him almost immediately upon arriving at Autumn Mountain.
After defeating the crayon boss, you can remove the red streamer from Peach's Castle that the Origami King captured. You can return to Overlook Mountain, where the tram had been enveloped by the streamer with the captured toad. Talk to him and you can get on the tram. Mario and Olivia will meet a Bob-omb who has lost his memory. It's a quick cutscene that plays during the tram ride, but you get a new companion to take you on the adventure.
After the end of the tram ride, you will have arrived at Autumn Mountain, a waterfall-like mountain where the leaves seem to be a day away from falling to prepare for winter. You can find the Sea Captain Toad right across from the tram. He will be the blue fish floating in front of the tram ramp on the right. Hit it with your hammer to convert it back to its original form. When you return to town, you will now have access to the ship to set sail to explore what is there.