The old town is a lovely spot in Stockholm. It is close to both Södermalm and the City Center up north and it takes just 5 min to walk from the appartment to the T-bahn, that takes you all over Stockholm. There are restaurants and malls for buying grosseries within 5 minutes walk too.
We stayed 4 people in the appartment, and that is doable. It is a small, but very welcoming appartment and loved that Agneta had made sure to have iron and ironing board available for us. We where attending a conference and thus this was terrific.