Thanks for the detail reply!
Yes, I've booked tickets from 2 different airlines.
Assuming the flight is on time at Oslo airport (OSL). I'll probably take 15 minutes to get off the plane, 5 minutes to run for the immigration control... hopefully not too many people (I don't need a visa).... and then run towards the baggage hall to collect my luggage (maybe another 10 minutes). After going through the customs control, I'll go to upstairs for my SAS flight to Tromsø!
But I'd like to know too what to do if my first flight... the one to Oslo arrive late, and I missed the connecting flight to Tromsø.
Are there any other ways for me to get to Tromsø on the same day as I've booked hotels in Tromsø.