I personally thing the blueprints are legit. Was at the park last weekend and everything I saw seemed to fit with these drawings. Also, I agree with what the video said, the drawing is the top of a stack of papers so there's multiple drawings there, not just one.
1. The footers already placed in the lake match the drawing.
2. The markers beyond the bridge are actually fake ans are there to troll.
3. I did notice markers in the area being cleared that match the location of some footers. speaking of the cleared area, there is no work being done down the ravine or behind the Racer.
4. Although unrelated, I googled the phone number on one of the earth moving equipment and its a local company. What other worktrucks onsite were parked in a way that I could not see any license plates. Specifically was looking for Idaho tags.