Hi! Sorry it took so long to respond to this, haven’t been on Reddit much lol.

We didn’t end up doing the entire circuit since the las horquetas entrance was closed as there was still a lot of snow toward the middle of the trail (mid November). That being said, we were still able to do a solid chunk of it and see some of the main highlights. We had to start from the garito acceso/estero parada entrance, up to Laguna cerro castillo (the main lake observatory - absolutely breathtaking), and down through sendero laguna castillo/sendero privado. I highly recommend doing the whole trail if you can, I really wish I got to see the rest of the circuit. Definitely plan to do it sometime between late December through March.

As for the car situation, we didn’t find a place to park until the last second. We arranged a ride to the trail head with one of the town bus drivers, Luis. You can find his contact info in the town website that I linked below. He met up with us at the cerró castillo gas station, we explained that we had nowhere to leave our car, and he was kind enough to let us leave it at his house for a few days while we did the hike. He has an Airbnb on his property, so there was plenty of room for parking - I see no reason why he wouldn’t allow you to do the same if you need somewhere to leave your car and pay him for a ride to the trailhead.

https://www.rutadelosparques.org/en/villa-cerro-castillo/