Hyde Park Inn

To what extent are 2 places? I need to get in the car (greyhounds) at Canberra Central Station Eddy Avenue, and I'm staying at the Hyde Park Inn (271 Elizabeth Street)

if you do not know your way around Sydney to catch a taxi is a 3-4 minute drive from your hotel to where you need to board your bus to Eddy Avenue

No, it is near the Museum station. You can get off the train at Eddy Ave, then take a train from 20/21 platform for the next step which is the Museum station and exit at Liverpool Street and down St. Elizabeth, less than 10 minutes on foot.

or use the train from the museum, disembark at the station and leave the door to the north (to get as close as possible to the Eddy Avenue), take a taxi (about 4 minutes) or Just walk along Elizabeth Street, Liverpool all the way to Eddy Avenue, its 10-minute walk