Using Google maps, the following info

Drive from Darwin International Airport back to kakadu and Jabiru town.
2 hrs 38 mins 252 km

Jabiru to Cahills Crossing 56 mins, 42 kms

Cahills Crossing, to Garig Gunak Balu National Park
10 hrs, 231 kms

An average speed of 23 kmph.

I wonder what the road is like?

How many river or creek crossings in addition to Cahills?
How many of these are tidal as well?
How deep any of these would be?

General condition of the road?

I remember the tracks in the Park itself, and they weren't too bad. Still we used to drive them slowly as we were looking for game.

Have to carry all fuel for the trip to and from jabiru as well. Plus all water and food.

With a 10 hour drive from Cahiil's Crossing to somewhere in the Park, officially there is no stopping except emergency stops in Aboriginal Arnhemland, so a long slow one day drive.

Thinking of this side trip for photography, filming, and maybe some fishing, along with scenic sight seeing. Unfortunately NO SWIMMING in the beautiful azure sea and white sandy beaches !!! Big crocs cruise those waters.