Stockholm
I have no knowledge as to whether this is, or is not, a possible route.
Looking at the destination in comparison with others, I would make the following points:
Stockholm is a fantastic city - a good leisure destination that is no more expensive than most other European cities. It's an all year place as the winters are cold and crisp and the summers hot and light (22h daylight)
Newcastle, the North East and Northumberland is an attractive leisure destination for the Swedes; shopping, shopping, shopping and country side.
Arlanda is a good hub airport. Lots of Scandinavian connections but also America and Canada.
Just some thoughts, when you compare to some pure leisure destinations currently served then Stockholm stands up.
It's not my money to risk so I'll leave the decsions to those whose money it is.