The fourth portal, as might be expected, can be found atop the hill known as Makeout Point. The other side of the portal isn't altogether that much different from the side you're entering from, save for the thicker trees and somewhat darker lighting.

The other side of the portal is significantly colder than the Mayfield side; frost covers the ground, and although it's not quite freezing, you'll want to bundle up. A glance at the sky reveals what you might have been dreading: glitch holes, in varying size, litter the skyline. The sun is hidden behind a set of thick clouds, creating a melancholy atmosphere.

The landscape around you is relatively flat, and you can't see too far beyond the forest ahead of you. It isn't until you turn around, facing the portal that you entered from, that you see the rising slope of the ground. The mountain rises high, higher than you can see from its base. There's a rough, primitive path heading up its slope, and for now simply hiking will be sufficient. As you get further, however, simply walking won't be enough: you're going to have to climb...

Somewhere, closer than you might prefer, a single wolf howls, and is shortly joined by more.

Better get moving.