How serious are you about climbing i wonder? The first thing is to give yourself a full weekend rather than 2 half day trips. You leave Melbourne at 7 on Saturday morning, its light at 5 or soon after. That's when you should be pulling into the car park (or rolling out of the pit having driven there the night before).
Hence:
Tip 1. Forget Booze nite Friday
Tip 2: Camp in the open that way you'll wake with the birdies
Tip 3: Get up & Climb
Tip 4: Go to a crag
Climb as much as you can Saturday and get back to camp at dusk. You can cook in the dark can't you ? It doesnt have to be gourmet. Keep off the coffee Sat night it'll stop you sleeping.
Sunday wake at 5 & climb as late as you can whilst still beign able to drive home safely. At least you have the sun setting behind you when you are going east.
Tip 4: wash face & hands & feet before driving
Tip 5: ensure you can both drive & swing the sharp end
Tip 6: dont stop for a 2 h dinner have a burger somewhere
Tip 7: get a car with lights
Tip 8: make sure the lights work & you;ve got a spare
This all worked in the 70s, dont knwo why its so hard to work out today.