We had a great stay at Lovisa's place. The appartment was small, but big enough for a short trip with three people. The kitchen had everything basic you might need. The bed was comfortable, but the mattress was pretty saggy, though I slept just fine. The only problem was the sofa as a sleeping place, because it was very saggy and my friend couldn't sleep all too well.
Especially the short walk to the tunelbanan station was great, but you could also walk easily to Gamla Stan. Södermalm in general is a great neighborhood with many restaurants and shop.
Although we never met Lovisa, she was very helpful and gave us many tips. Thanks!