Head immediately to the right, not on path, and there is a Psi-Card to grab. Now get on the path and head towards the lake, the other way will take you back to the main campgrounds. When you get to the beach a scene will play and you'll learn about the gypsy water curse on your family. During the scene you'll probably notice the Psi-Card right behind you, grab it when the scene ends.
After grabbing that card head left (when facing the bridge you came down from), not too far is an entrance to the UTS, down a bit further keep your eye off to the right in the plants and you'll see another Psi-Card. Keep going and you'll find Cruller again, although you can't get a canoe without an Oarsman badge. Head out the bridge on the other end of Cruller's place to walk the boardwalk over the lake, but after not too far cotton candy head stops you and you can't get past him.
Head back to where we started and keep going straight past it and you'll find a little path that leads you straight to a Psi-Card. Turn around and head back and you'll notice up and to your right is a light pole on a ledge you can jump up on, then from there you can jump up on another one with another Psi-Card. Continue along this path that's up here and you'll see two tree branches sticking out of the wall you can swing on and jump up to yet another Psi-Card.
That's all we can do out here right now, so head back to the GPC area. Follow the path straight ahead and you'll encounter some campers head for a short scene. He'll mention some stuff about Sasha Nein's secret training which you are now right next to. Right here is also a path back to the Main Campgrounds so if you want you can head back there to buy some more Psi-Cores; if you have all the cards I've got so far we have enough to complete 5 Psi-Challenge Markers.
Otherwise head through the log next to the kids, when you are halfway through you'll notice the top is gone, where the top comes back right before you enter the GPC area there is a Psi-Card on top. Jump up where there's no top then get on the top part to get the card. Now enter the GPC area.