First, let me start by explaining the people that you will deal with: the owner, Jan, was great to work with from the time of booking all the way through our stay. He was not there physically, but was easily accessible by phone, any time (we called him early once!). It is obvious that he is an active manager of the property, always looking for ways to improve and ensure a great stay for his guests.
His caretakers, husband and wife, are fantastic as well. They do not speak English, but Jan is always available to interpret. With the little Spanish I know, I was able to communicate back and forth with them just fine. Super friendly and helpful folks. The dogs that live on the property are great as well (keep them away from the chickens!!!)
The property itself is perfect for low-key, nature-loving groups, couples and families. If you are looking for a 24-hour party, I would stay right in Montezuma. If you are looking for a place close enough to walk to town, yet really secluded, this place is great. My favorite part of the property is the Rio Cedros which flows down, along the property, into a large, deep freshwater lagoon. This lagoon stretches all the way to the ocean. We had a lot of fun in this area. The beach is okay for swimming (watch the rocky areas), great for shore fishing, and the lagoon is one of the most refreshing places I have ever experienced. I highly suggest exploring a ways up the river (you won't regret it!), one highlight was having a troop of 7 or 8 Capuchin monkeys climb down from the canopy and hang out by the water with us! We were very close to them, far away from the nearest tourist. A very special experience.
The house itself is open air, in part. You will share it with some critters. It was fine. My wife, son and I were not put off in the least. In fact, it was great! The bedrooms are more private and very comfortable. I think it would get very hot in the house during the day, but we were always doing activities. There is a room with A.C. but we had no need for it.
In the area I would recommend spending a day at Cabo Blanco Reserve by Cabuya. The falls and beach at Montezuma are great. If you can make it over to Santa Teresa you should. But, by all means, spend a lot of time right at the lagoon, away from the tourists and closer to the authentic Costa Rica. Pura Vida!