My family stayed in this house for 4 days, including our 9-month-old baby (for which the property manager had considerately arranged to have a pack-n-play set up). First of all, the area is really cool. It gets you off the beaten path of La Fortuna, but is still close enough to go there for groceries or dinner a couple of times. It is located near a tiny village called El Castillo, right in the heart of the jungle. El Castillo has the most amazing zip-lining available in Costa Rica (SkyTram), a great "soda" for breakfasts or even lunches, super friendly people (both Costa Ricans and a handful of interesting American ex-pats and retirees that are more adventurous than most 20-somethings I know), amazing hiking trails, and quick access to any other activity you could imagine. The property manager, an American named Allen, lives in a neighboring house year-round, and was more than happy to help us set up any activity by calling for prices or reservations. He was funny and a wealth of information, as well as being a phone-call away for any concerns with the house; he was like our own personal concierge! Up the road from the house is a world-class spa if you want a massage or to eat dinner at their restaurant. Some of the people in my group went horseback riding with a guy named Lelanders, the local cowboy, and had the most incredible ride (& we're all horse people, so we're harsh critics!). Lelanders has gorgeous appaloosas that are fit and very well cared-for, and he took them on a ride for over 4 hours, deep into the jungle on private land of his family's, to a huge waterfall where he had built the trails himself. They saw incredible jungle wildlife, including a 6-foot boa constrictor! And of course, the jewel set into the center of all of this is the house itself. Gorgeous, gorgeous, gorgeous! It made us want to buy property ourselves to try to recreate it. It has a very clean pool and hottub that look out over an expansive valley - totally private. We relaxed in that hottub and enjoyed amazing views, sunsets, and stargazing every night. There's a bathroom down by the pool and rec room, which has an indoor-outdoor ping-pong table (super fun). Each bedroom has its own private balcony overlooking that valley, and just laying in bed in the mornings you can gaze out at the colorful jungle birds and butterflies. The grounds are beautifully landscaped, the kitchen has anything you might need, there are plenty of towels and blankets, it's quiet and peaceful and relaxing.... I can't say enough about how amazing this house is!!!
Tips: bring a light jacket and long pants; it can get a bit damp and chilly in the rainforest. The house doesn't have AC, but definitely doesn't need it. If you're scared of bugs, maybe scratch a stay in the jungle off your CR list; the house does have its 6- & 8-legged residents (and along those same lines, any food you have or bring needs to be sealed in airtight containers or else it will become bug bait). I can't imagine staying at this house without a car; it's kind of isolated and the hills would be prohibitively long and steep for regular trips to town on foot. We had a rental SUV, but never needed to put it into 4WD, but I could imagine a really different landscape during the rainy season. Allot plenty of time for any drives, because the roads are super twisty, totally unmarked, and rife with obstacles around every turn. For reference, it took us about 3 1/2 hours to get to the house from the airport in San Jose, 30-40 minutes to get to or from La Fortuna, about 2 hours to get to Rio Celeste, and a grueling 6 hours to get to Tamarindo (we got a little lost, and also hit massive road construction). After we booked this house, the owner sent me very explicit directions from San Jose, complete with a ton of reference photos - it was the only drive we made during our whole trip that we didn't get lost!
In summary - book this house! It will be the best vacation decision you could make!

We just returned from a 10 day trip to Arenal and it was amazing! We were extremely active on the trip (horseback riding, zip lining, hiking, etc.), but at the end of a long day, this house provided the perfect retreat! The grounds and gardens are beautiful and the house has all the amentities you need! We saw more wildlife at the house while soaking in the hot tub than anywhere else (howler monkeys, capuchin monkeys, toucans, parrots and 100 other bird species). The individuals the owner has looking after the house and the guests were truly amazing! Emilce and Luis were wonderful and their presence helped us to truly experience and enjoy Costa Rica's food, culture and people! Emilce's home cooked meals were fantastic and enjoyed by all! Their son, Fabricio (and his daughter Emily), were lovely. Alan, from Birdsong B&B (up the hill) was helpful - arranging excursions and making recommendations for restaurants. He even took us to Rancho Margot one night. Greivin, the property manager, was wonderfully helpful as well! A massage from Krissia @ Nepenthe (up the hill) is a must! Tomas and Hannah from La Gavilana Herbs and Art were great - they arranged the horseback riding tour with Guillermo and his brother. Hannah is a very talented artist and Tomas is a fermenter - worthwhile visiting their shop for fresh baked bread on the next ridge (it is quite a walk!) The soda and the supermercardo in town were also convenient to have nearby. A 4x4 car is helpful in this area to get up and down the hills.