This place is in a very quiet, pleasant residential neighborhood. It is in the northern part of Ballard and is a couple miles from downtown and the busier, more commercial part of Ballard. If you want to go out in the Capitol Hill / downtown area at night and don't have a car, it's at least a $30 Uber/Lyft ride back to the treehouse. If you need to get to Sea Tac airport, it'll be a $60-$70 Uber/Lyft ride. You can also take public transportation to Sea Tac, but it will take about an hour and a half. There is a bus (the 28X) that runs during the day (and maybe later?) that will take you downtown. If you don't have a car, you may want to consider staying somewhere more centrally located.
The treehouse was cute, compact, and clean, except for dog hair on the couch/futon. It's pretty close to the hosts' house (about 20 ft away, but connected by a back patio). The view from the Murphy bed on the second floor is of the grass and an old couch in the neighbor's backyard. It's not an experience of being "in the trees." I noticed that there are no photos in the listing of this view, only the view of some branches pressed against the kitchenette window.
The bathroom is very nice. The shower has good water pressure and the shower and bathroom in general are a good size.
Check in and communication were good.
The mattress on the Murphy bed upstairs is very, very firm and I found it quite uncomfortable. I checked and it's an IKEA memory foam mattress. It's not very thick. I assume this is the bed most people would choose to sleep in since it's on the same floor as the bathroom. With cleaning and service fees, my total nightly charge was $200. This is on par with the price of several hotels downtown. For $200 a night, this place should at least have a more comfortable bed. Yes, there is also the option to sleep on the futon downstairs, but 1. it's a futon and 2. you would have to climb the stairs and maneuver past the open Murphy bed if you need to go to the bathroom at night. But for $200 a night, neither the uncomfortable bed or futon are adequate options.
I found the TV hard to use. It was hard to do simple things like search for shows and select shows. On the third day I was there, I tried to use Hulu like I had the previous nights and got a message that the TV no longer supports Hulu. I'm guessing it's due to the age of the TV. I also used the washer and dryer on my last day. The washer has a pretty small capacity, so be prepared to do multiple loads if you have a lot of laundry. The dryer did not work very well. I was rushing to get my clothes dry before checkout and I had to give up and take them to the laundromat nearby.
My biggest issue with this place is difference between the quality of what is offered (bed, TV, dryer, etc.) and what the nightly charge is. If the host wants to charge $200 a night, the TV should be updated, and the upstairs mattress should be replaced with something more comfortable. I do think it's a cute, unique place, but it needs some updates so the guest experience is in line with what the host charges.