MarkO
Its about 9 or 10 NM from Runaway Bay so call it 20 km each way. How long depends on how fast you travel.
If your going on a weekend beware of the bigger boat wakes that can bounce your passengers / kids around.
90 lt will be fine
If your eating at the cafe you can look up the menu on line
Had fish and chips with local snapper last trip not long ago and the fish was very soft so not sure who was cooking but it was not as good as it has been in the past.
Have fun
Cheers
Chimo