Post #2 has been updated with additional information on activities. At this stage, we are still having problems securing the final piece of the puzzle, the dinner on Saturday night. Rest assured, this will come together soon, but we may open up reservations for activities first.
Saturday
Saturday morning activity is a private tour of the Sydney Opera House. The ticket cost is $42 and will need to be prepaid.
Sunday
Bus tour from Central Station (DEP 08:30) to HARS (ARR 10:00) for the day, including a stop for lunch at {location TBA} on the return. On the return journey, the bus will stop at SYD Domestic T2 & T3 (ARR 17:30), before making its final stop back at Central Station (ARR 18:15). For this reason, if you are flying out on Sunday night, you can bring your bag with you to go under the bus and eliminate a return to the hotel to checkout in the evening/mad dash to the airport.
Bus ticket is $55 and will need to be prepaid, while HARS* entry is $20.
*There may be scope to do additional activities at HARS for those adventurous, currently working out details.