Check in - this is incredibly simple and there were no issues at all, although the host was available and communicating should there have been.
Location - very easy to get to, take the Link Train from SEATAC to the International District which is three dollars and it's a short walk up hill to get there, takes half an hour. Alternatively you can get an Uber/Taxi for $40/$50 and it takes half an hour. From the apartment you can easily get into Seattle, we walked most of the time, very close to some great places. Particularly liked the coffee shop (Tougo Coffee) at the top of the stairs on the corner of Yellar/Broadway and some of the restaurants that the host recommended are great in the neighbouring streets.
Feel like I should mention if you haven't been to a US downtown city before then you may not be familiar with the homelessness and drug addition issues. Unfortunately Seattle is no different and South Jackson Street, which runs adjacent to the apartment complex, has quite a few issues with this. We never felt unsafe and the apartment is extremely secure so no need to worry about it. If you always take the steps up towards downtown you will avoid that street anyway and it's more at the lower end near the stations that you see most of the issues. Do not be put off, this is also true for some of the streets next to the 5 star hotels. It seemed to just be a city issue overall which is true for most big US cities, from our experiences.
Apartment - great spot with lovely little extras and personal touches that make the stay extra convenient. Very comfortable bed, good amenities and everything you would want from an apartment rental to be honest. We loved having morning coffee on the balcony. You won't be disappointed.
Recommendations - walk down to the Harbour and into Pike Market (we did a great 10 mile walking loop from the apartment), do the space needle for the views and if you have time and a car get out to Mount Rainier National Park (July to Sept only).
Overall this is a fantastic spot for two people or a small family to stay in the city while enjoying the freedom and convenience of having a little home away from home. Great find, great host and a great stay was had by me and my wife.