Yes you can, however there is no direct line and trains have reduced frequency on weekends.

We were in the highest section in row H at Keith Urban last weekend door 65 and it was amazing

No not really.

We moved down to the floor . The view from 66 was ok. You could see with binoculars stage and the side screens were large enough to see them

I agree totally with the previous answer. Train from Central to Lidcombe, change platforms to the "Olympic Park" platform, exit station, turn right and a short walk 'downhill' from the station there. You need an Opal card for the train.

Re the Paul McCartney Show - as I was a guest, I am unsure how the tickets were bought or how long before the show date. As our seats were assured and we had to collect the VIP package items, we had dinner first, then went to the Show. Also I was told that the evening before, people arriving earlier found the security checks slower due to the number of people entering at that time. I can't answer your question properly.

You will have to check the seating arrangement for the particular concert, Can be found on ticketek or whoever's promoting the events website.

I'm it quite sure. I sat in section 12/G with no issues at all. 18 was on the other side off to the left of me. It didn't appear to have any obstructions at all. No poles etc I guess it will depend on what event you're going to they may set up the arena differently for different events.

I found the worst part of those seats was the reverberation of the sound off the back wall. Was up there once for Green Day.