We spent a week at this property with 6 total adults. We had a great time and are already planning our next trip back the property.
The "cabin" was quite nice and provided a nice base for us to hang out, cook and share meals, get some great sleep. It is perched up on a hill, so unloading and loading can involve some steps up from below, or a drive up the steep driveway.
The deck is a great place to hang outside. I loved the east/west orientation - you can always find sun or shade depending on your preference.
The water pressure is a little low in the show, but hey, this place is mostly off the grid. There are some picky layout / design things with the kitchen, but everyone has an option.
The only issue we had was a pesky smoke detector battery failing on Sunday night after we all went to bed. Yeah, you know that chirp you can't place, you sit awake listening... and listening, and then there it is. This one was a bit obnoxious and way high up in the vaulted bedroom ceiling. We texted the owners and they came by with the extension ladder and addressed the problem. I don't think any of us were excited about the issue at 11pm on a Sunday night, but it was addressed quickly and we had great nights sleep through the rest of the week.
The lake is very pretty. It's kinda of a big pond with a deep hole in the center. Did not go swimming, though there is a swim to dock and access. As a kid, I would have gone in. As an adult, I tend to avoid muddy bottom lakes with a lot of vegetation. All that said, the paddle craft is great to get out on. We saw opsrey diving for fish, deer eat along the shore, baby ducks (!), plenty of birds, and our friend caught 3 rainbow trout in 5 minutes flyfishing off the rowboat.
The cabins are spaced out well and we rarely heard a peep from the other guests. Most of the time, it was only apparent there were others around when we heard them on on the lake trail or someone was on the water or at the dock.
This place feels remote, but is barely 20 minutes from downtown Bend. Tumalo Falls is a relatively easy hike - the hiking and mountain bike trails a plenty! Really quite nice all and all.
I think you and your family / close friends would have a very nice time.