If time (travelling) is of the essence and you're not travelling during the wet I'd make it Melbourne, Adelaide, Alice, Tanami Track, Halls Creek, Broome.
The
Tanami Track is dirt for 800 to 900 km but easily done in any normal clearance 2 wheel drive, such that it's a misnomer to call it a track in this day and age. The country side, especially at the Alice end is fantastic. The only fuel once you leave Alice is at Tilmouth Well, about 2-3 hours out of Alice from memory. Next is Rabbit Flat, run by an eccentric family that are only open for business Tues to Thurs if I remember correctly, then Balgo, an hour or so prior to Halls Creek.
Other than the Tanami Track all the roads are sealed.
There's no speed limit on the open highway in The Territory, though if the coppers think you're driving unsafely, you may have some explaining to do. I'd recommend a max of 80 kph on unsealed roads. I learned the hard way on one trip, two trees and a blow out
, when road conditions change in a second, with no warning.
As a rough guide, I can do MEL - DRW in 3 days, driving a diesel Patrol, about 12 hours per day. MEL then overnighting Port Augusta, Alice, Camp along Tanami Track, Halls Ck, Broome would be quite achieveable in 5 days if your vehicle's up to it. Cruise control is
well worth it !