The thing to remember is that a lot of the "extra" stuff you may decide to bring along will probably stay in your car and never come out... all you really need to have on you while you play is camo, rig, radio/headset, goggles, gun(s), mags, some water and power bars/jerky. Real food, spare clothes, extra batteries, gas, sunscreen, bug juice, bb's, tools, the rest of your water, "normal people" clothes for the drive home etc etc all just sits in the car or the staging area, depending on what it is. At a long game like Rawdon, nobody will mind if you take a few minutes out to go to your vehicle for essentials or resupply in your staging area.
All I'm saying is I wouldn't worry about being weighed down.
But if you're going to a Rawdon game, for the love of God bring sunscreen. You will use it or fry. Maybe bake is a better word, but either way it will be bad.