With no FanVision this years it makes it harder. I think the FM channel is 99.7(or 97.9) so try to take an FM radio. I dont think there is commentary airing at the track (Adelaide used to but a waste of time).
You can walk the track straight after the race. Anytime from Thursday to Sunday you will have issues with security. Pit lane walks are for Paddock Club and a few other tickets only (corporate and V8 Supercars)- I am not sure whether Brabham stand gets that, but I dont think so.
I think drivers do a autograph session on the Thursday, but I have never been, so check times. If Brabham stand gives access to the “Gold area” head to Paddock Club entrance from 0900 to 1030 in the morning and the drivers arrive at the Paddock entrance- most happy for a quick hello, sign & photo if you wish- Vettel VERY good at giving his time. I would say similar on the way out but times vary of course.
Most drivers stay at the Crown Towers so you could get them in the morning- but most would be to the car and then out, so I think another time waster.
Enjoy your first GP you will be stocked. I took my wife to her first F1 last year and she could not believe how LOUD they are !! LOL!! Cant wait-GO WEBBER!!