Train or conxion to BNE

Somehow we can fly direct to Adelaide but not to Canberra from Sunshine Coast Airport and so once again I'm trying to work out the best way to do that to go visit mum. Do two flights MCY to SYD then to CBR for $$$ or get down to Brisbane.

I can get to Nambour and catch the train but haven't done that before to the airport. The conxion shuttle is handy but expensive and takes three hours.

Any thoughts on the train option?