You absolutely can bring food and water to your campsite. You can also bring alcohol and a barbecue if you'd like. You can bring food and sealed water bottles into the venue.
As far as premier camping, I feel the shuttle is the best aspect. You get to go in early, and avoid the long walk. Otherwise, if you just want to go to sleep when you're at camp, go premier. If you want to party, go general.
the situation with bringing food and beverage into the concert itself, however, always seems to be up in the air for a while. no matter what though, at least they let you bring water in. some concerts don't, and they can go to hell