River Tunnel

The River Tunnel Area is a area where it is right under the swamp and is where the bridge is at. At the moment only a song is played when you enter the area.

Where to Find River Tunnel Area
You can only use a XL Truck or Val's All-Purporse Hauler to see it, there is a high chance that the creator is adding boats or a submarine in game.

There is now a way to get there and its by swimming. Defaultio must have done it on purpouse or its a glich. You will also get hurt if you drive there in a car though.