You should contact DIBP about any change of address after you pass the citizenship test but they won't automatically update your citizenship ceremony location unless you ask them specifically to do so.
Personally I'd not recommend not going overseas for an extended period before your ceremony as they won't email you, only send a letter to your registered address which can be sent just a couple weeks before the ceremony. It can be a big pain not being able to travel, I personally had to forgo some work related business trips because I didn't know which ceremony I'd get allocated to...