The River Road is a large ziggurat-looking area made of brown square tiles and stairwells, with plants growing out of the cracks.
Entering from Shield Owl World will place you next to a pink bear, 2 levels above the pipe to the docks. By going up the long staircase on this level and then down the smaller one, you can reach a door leading inside to a large complex.
The dark complex inside is made up of many winding corridors and pillars, and is home to various strange creatures, which make noises if you interact with them. Equipping the lantern effect in this area will light it up, letting you see better.
From the door outside, you will enter into a large hall filled with pillars. On the very left side of the hall is an unfinished face, sectioned off by construction cones.
From the entrance hall, going down to the southwest will take you through a long, narrow corridor into the lower part of the area.
In the lower half of the complex there are many doors leading to various places to explore.
To the southwest is a corridor lined by large red curtains, leading to a curtained hallway with 2 hanging pieces of meat and a large pink bull blocking the way to a door on the other side of the room. Chainsawing or howling at the bull will make it move forward and let out a loud 'moo'. Doing this until it moves offscreen will let Urotsuki access the door at the end of the hallway, which leads to a large area filled with many balconies and doors.
From the entrance, going through the rusted door at the end of the balcony will take you to a large store-room filled many hanging pieces of meat and a green man with a camera for a head, and going through rusted door in the middle of the balcony will take you to a similar area connected by ladders.
Making your way down the ladders from the middle door, the first room on the left will take you to an empty locker room, and the door at the very bottom will take you to a small room with a few lockers, a strange squid-man and an orange kettle.
Back to the main area, to the south is a short corridor with a red arrow on the wall, pointing out a doorway at the end that leads down a long dark staircase to an even longer ladder. At the bottom of the ladder is a bricked area, with strange organic-looking graffiti decorating the walls.
Continuing to the left through a small room with a log, you will find a very tall room housing a large chairlift, with a blue creature sitting over in the corner.
Following the instructional arrow on the floor, walking around the chair and interacting with it from the left side will let Urotsuki ride the chairlift up to the top of the room where there is a door to Christmas World, with snow spilling out of it onto the lift platform.
Once again in the main area, to the west is a door leading to a small platform with a staircase in the upper right corner, and a ladder leading down into an empty waterway. Going up the stairs here will take you to a small shack outside the storage area on the Highway.