SAS is a member of Star Alliance, meaning that many of their flights are code-shared or can be interlined with local Star Alliance partners. Therefore, you can take advantage of a one-ticket flight to, from, or via Copenhagen even if your origin or destination is not directly served by SAS. Norwegian is not a member of any alliance, but they offer connecting flights from Copenhagen to their European destinations on one ticket with an intercontinental flight.
Parking capacity at Copenhagen Airport was greatly expanded in 2015 with the construction of a new lot as one of the first phases in an ambitious airport expansion plan scheduled to roll out in the coming decades. There are several lots: those near the terminals are very expensive, while the further-flung ones are cheaper (but have free shuttle bus service to the terminals).