My first mistake was expecting Stockholm to be very Viking. I was wrong ! Infact, Stockholm as a city was only founded a few hundred years after the Viking era. The original "most important town" in Sweden was Sigtuna and that is full of evidence of Old Norse and Viking life.
Both Sigtuna and Stockholm are based on the shores of Lake Malaren. In the Viking era this lake was an important bay leading out into the Baltic and across the seas from inland Sweden.
My husband's god-son lives in Sweden and offered us a stay at his Stockholm apartment and also his summer house by Lake Malaren. It was a hot, sunny and very beautiful ten days.