Yeah I reckon that's a good place to meet up. I know it gets a bit crazy around lunchtime but we'll be going fairly early in the morning anyways so should be fine.
Location:
https://maps.google.com.au/maps?q=McDonald%27s+Thornleigh&hl=en&ll=-33.72976,151.083354&spn=0.002157,0.004128&sll=-33.729711,151.083212&sspn=0.017328,0.033023&t=h&hq=McDonald%27s&hnear=Thornleigh+New+South+Wales&fll=-33.729749,151.083416&fspn=0.002157,0.004128&z=19
Edit:
I just noticed there's an "Overflow" car park just around the corner aswell:
https://maps.google.com.au/maps?q=McDonald%27s+Thornleigh&hl=en&ll=-33.727743,151.082724&spn=0.001079,0.002064&sll=-33.729711,151.083212&sspn=0.017328,0.033023&t=h&hq=McDonald%27s&hnear=Thornleigh+New+South+Wales&fll=-33.72795,151.082511&fspn=0.001079,0.002064&z=20