How early are you getting there? Isn't State of Origin on Wednesday morning? I know they let you into the area early, (think it was Wednesday night when we went down in 2010).
The fact the game isn't on Sky Sports might hinder you as well.

Do you get in at a concessionary price Dave?

Just found out that Glasto has a 4G tractor this year, so if the SoO is streamed, there's a chance of watching it onsite

they have a free wifi zone on a tractor which will move round the site, they are announcing on twitter where it will be at each time, apparently has a 10m radius (metres not miles )

i always try to cut myself off from the outside world for a few days at glasto, going to try again this year so i can watch the game when i get back, not many RL fans in our group luckily

premier sports have a web player don't they? - might be best option though one or two, ahem, unofficial sources knocking about,