Tips and hosting for a cycling family in Sydney

Hello

We are a family of 6 ( 2 adults and 4 kids 5-7-11-12) and are travelling 13 months with our bicycles. We started from Toulouse in May, cycled to St Petersburg then took the transiberian to Baikal lake and cycled to Mongolia. We are coming to Sydney 1 week from 7 to october 15th by plane. As it is going to be very short, we do not intend to cycle there but stay in Sydney and then take a train to the Blue Mountains to spend 3 days there. We are looking for a place where we could leave our bicycles during this time. I know there is something in the airport but it is really expensive. Could you give us an advice ? We are also looking for someone to host us 1 or a few days there, but won't be cycling in your country.

If you read french you will find more information on our blog :
allonsvoirsilaterreestronde.over-blog.com
Thanks for answering

Sandrine, Philippe and kids