Isn’t the PS on top of some hill? It’s in the press picture with Danny and in the season previews with Double Dutch slipping and falling.
Yeah it's on a hill that requires hiking. It's likely near the coffee RB location; teams may even travel directly there on foot (walking uphill from the Roadblock to the Pit Stop).
The Leg structure is likely as follows:
Pit Start at El Peñón, Guatapé. Teams climb up and retrieve Detour clue.
Detour in Guatapé (teams take the colorful cars from El Peñón to the town proper, as seen in many previews with Sunny/Bizzy saying "we're in a race around the world!")
Teams travel by boat across the Guatapé Reservoir- however long, we do not know.
The Roadblock/Pit Stop/paragliding Roadblock in Leg 4 are all across the reservoir from Guatapé, either fully or partially, in a lush, more mountainous side of the lake.
From a logistics perspective, if teams are only provided transport on the ground in Guatapé, and then a boat, it wouldn't make sense for teams to need ground transport
again between the Roadblock and Pit Stop. Otherwise, they likely would've stuck with ground transport, either taxis or the buggies seen in the previews, the whole leg.