A family ecotourism project on the side of Cerro Guazubirá, and the most straightforward way to actually walk in Villa Serrana rather than drive through admiring it. The park has marked routes of different lengths, published walking times, and fixed visiting days and hours — all of which is unusually organised for rural Lavalleja.
What they are selling is biodiversity: native woodland, the birds that go with it, and the particular scrubby hill landscape of the Sierras del Este that most visitors to Uruguay never see because they stay on the coast.
Check the opening days before driving out — they are not open every day, and the road in is unsurfaced. The WhatsApp number below matches their Ministry of Tourism registration.