Check-in was easy: Since we didn't have mobile data, we informed Collin that we were coming from the airport. We followed his instructions for using the call box outside the apartment. We didn't get it to work on our first try but thankfully he was in the apartment and responded immediately with instructions via the call box (i.e., to open the door when the box shows 0 and the buzzer sounds).
Apartment is nice: My wife and I loved the place. Aside from the clear Harry Potter theme, the unit had some plants, high ceilings (12ft tall?), floor-to-ceiling windows, and a spacious private room. There was some noise but we sleep with white noise on so it didn't really bother us, and we didn't have to make the white noise loud.
Collin is an awesome host: He responded to all our messages quickly and was very helpful all throughout. Thanks again, Collin!