Travel from Kiruna to Stockholm

My friend and I are visiting Sweden this Christmastime. We're starting off in Kiruna and staying there for 3 days. Beyond that we don't have any real plans but have to fly out of Stockholm 4 days after that. We've considered taking the train straight to Stockholm but I feel like we might be passing up a lot on the way. Are there any towns between Kiruna and Stockholm where we should get off of the train and visit for a while? Any suggestions will be greatly appreciated