They are, I understand putting a new crane and wharf in place there, especially for the Abrahms. I seem to remember a media release somewhere about it.
To be fair - the crane and wharf upgrade was always going in irrespective of an Oz Abrams purchase. The Territorian govt had earmarked an entire facilities improvement programme in light of attracting and keeping US interest up. The shared training area helped cement that upgrade. So the crane and wharf bump was originally tagged approx 3-4 years ago.
The crane and wharf bump was also a reccomendation after timor '99. I remember being there in 99 and darwin harbour was like a UN shipping party. It was pretty apparent that apart from Oz logistics problems, the italians and portuguese were also struggling to offload concurrently.
The culmination of wharf choke during Timor and the addition of a bigger US presence with stored training always meant that upgrades were necessary with or without Oz abrams.
Re bridging, I was always under the impression that all main bridges in Oz were NATO compliant? The reason I raise it was that I was involved with some planning for wind turbine farms in Oz, one of the criteria was that the access roads had to meet their shipping standards - and the Int'l wind turbine shipping std is based on the NATO min height requirement of 5.5m.
So, any MBT's going along main access routes (be it rail or road) must be able to fit through 5.5m tunnels or points. IIRC, Queensland and the NT have the most compliant main roads/routes in the country.