A good question.
A local answer.

Confirm the restaurant serves both meals on your exact day and can accommodate any dietary needs. A hotel restaurant may not operate every night.

Check each park's managing authority first: ACT and NSW sites can have different entry and vehicle rules. One advertised pass may not cover both systems.

Shortlist places with a children's menu, high chairs if needed and a table for eight. Book ahead because a large walk-in group can be hard to seat.

Compare a lower-priced room plus a short taxi with a pricier walkable hotel. Check late return transport after the wedding.

Check the garden's current season dates, location and any event shuttle first. A suburban bus route is unlikely to take you right to a rural entrance.

Choose one nearby nature or country outing based on drive time and weather, rather than a long return trip to Sydney.

Allow at least two full sightseeing days, with a third if you enjoy museums slowly. Put nearby institutions together rather than moving across the city between every stop.

The accommodation may accept bags before check-in even if the room is not ready. Confirm that first; it could save a separate storage fee.

Group the national institutions by precinct and use buses or an occasional taxi for the longer gaps. Canberra's sights are spread across the lake.

Choose a car park based on its all-day rate and access to both the shuttle and city shops. Check closing time and event road changes.

Compare the official trail lengths, gradients and current closures, then choose by the landscape you prefer. Mount Ainslie has a strong city-view reward; Black Mountain can feel more bush-focused.

Check current bike-hire operators and their pickup points before the trip. Ask for a suitable size, helmet, lock and return hours.