Qantas operate several flights each day (an hour to an hour and a half long) from Sydney. It is well worth exploring options via the net (as per the given links) and booking well in advance, as fares routinely vary from as low as $100 one way, or even less, up to several hundred dollars one way.
There is a daily service to and from Sydney, which takes about 8 hours. When the train is not very full, this can be a most relaxing journey through varying countryside. For fare and timetable information visit the CountryLink web site. Advance bookings are half the price of regular ones.
A number of coach lines operate between Brisbane and Sydney via Armidale. Greyhound Australia may be contacted for details. From Sydney, the journey usually takes slightly longer than the train trip (but the bus fare is usually also slightly cheaper than the train fare).
Driving Sydney to Armidale is approximately a 7.5 hr drive on the New England Highway.
The alternative Buckett’s Way takes about the same time and is far more beautiful. However, it is more demanding driving, you should travel during the day as you may encounter kangaroos and wombats at night, and although you only need to turn two corners between leaving the Pacific Highway just north of Newcastle, and joining the New England Highway at Uralla, it is easier to get lost! The first turn-off from the Pacific Highway, in particular, is easy to miss.
Brisbane to Armidale is approximately a 6.5 hr drive, along the New England Highway.
If you are coming from the coast at Coffs Harbour, travel along the scenic Waterfall Way. Again, look out for kangaroos if travelling at night, dawn or dusk.