Not sure what weeks away means.
RDO can only be taken at "home" so you have to return to your domicile at some stage unless you elect to take them down route.
That said they do some long deployments from time to time.
Where they are recruiting for, BME & DRW (?) tend not to do these long away trips. Mainly CNS!
When away you receive overnight allowance - not sure what it is but I think it is approx $100/night tax free. From that you feed yourself so up to you how much you save or otherwise!