The apartment is in the heart of Gamla Stan, minutes from all the shops, cafes, Royal Palace and Nobel Museum. its also just up the small hill from the metro. That said there's no bar/restaurant etc near the apartment so we found it quiet in the evenings which was good.
Eating out in the evening in Stockholm isn't cheap so the option to cook at the apartment is a good one to have. There are two good small supermarkets nearby, the best one at the Metro station. Don't forget (we did) you cant buy wine at any shop, only special ones. Search Google maps. The nearest one is about 10/15 minutes away towards the city centre.
We were surprised how many businesses & attractions did NOT take cash .. only card. So ensure you have a card that doesn't charge you fees / high exchange rates for using it in a country other than your own. Our (UK) Monzo card was very handy.
Great communications on our arrival day. Our plane was late but hosts were there to let us in and show us around. Thank you.