Two of you, two witnesses, one beautiful spot
Australian law needs two witnesses aged eighteen or over. That is the only crowd required. If it is genuinely just the two of you, Sharon will arrange witnesses — it happens often and nobody finds it strange.
If you do not know where yet, that is half the fun. Sharon knows which Hunter vineyards will let you stand among the vines on a Tuesday, which Newcastle headlands catch the sunrise without catching the wind, and which Port Stephens beaches are empty at seven in the morning in March.