Draft Overview Route:

From Stockholm, we cycle toward Trondheim, Norway and start following the Eurovelo 1 to the North Cape. Then  on Eurovelo 11 dropping down in Finland to Oulu. Here is a decision point and reevaluating the time left to reach Stockholm. We will probably take the train to Helsinki. 

From Helsinki, we will  cycle much of Eurovelo 10 route through the Baltics and northern Poland, part of Denmark and back to Stockholm.

Thank you fellow cycleblaze member Simon Thread for recommendations and information on Eurovelo 10 route.