If you have spent a few hours at Gamla Stan, and want to go to Djurgården, you should take the Djurgården ferry.
To get a good impression of Stockholm: get into a boat. At the palace at Gamla Stan you can do boat tours. One hour tours cost only 8 euros per person.
As Stockholm is made up of 14 islands, one of the best ways to get around is by boat. We boarded a boat at the Royal Palace and went off to Djurgarden. Then from there we went by boat to Sondermalm.