45 minutes to collect your bag and make your way to T1 is definately possible. Its quite a walk to T1 (20 mins i would say), but I would definately walk it briskly and not wait for the landside shuttle bus if its not already waiting for you...

If you miss the flight just take the next train to Frederikshavn. Its quite comfortable (I easily sleep on it in standard class), but will take you something over 4 hours I would guess to get to Aalborg. (It takes just over 3 to get to Århus and Aalborg is about 100km further) If you want to check out the train timetables, go to www.rejseplanen.dk. Also, you can pre-book seats on the train online for 25DKK.

You will also be able to chek in online for the sas trip.