As Max has stated there is quite a network of bikeways and theoretically you could ride from Alderley to Ipswich mostly on bikepaths
BUT at various points you will have to
cross busy roads
also some of the Bikeways are good - some not good at all.
The bikeway beside the Western Freeway is relatively good but there are still some busy roads to be crossed and the descent onto the Jindalee bridge is a worry.
You might get a bit lost after that
A problem is that the bikepaths are relatively disjointed and you will struggle to link them up. Directions are sometimes lacking.
But it is worth a go, be prepared to make a few wrong turns and be prepared to catch the train home !
there are some good new bikepaths between Goodna and Riverview (Ipswich) which are due to officially open soon, possibly they are already open.
Hope that helps,
Steve