My partner and I love camping and usually go on a trip two or three times a summer.
Keeping stuff cold for 5 days will be a struggle but not impossible. You'll need a good quality ice box. Techni-Ice make great ones
http://www.techniice.com/ or the Esky branded ones like this
http://www.bunnings.com.au/esky-65l-...heels_p3240360 work really well also. I've got one of each - big techni ice for food and the small esky for drinks - saves opening the food box so regularly. It's a good idea to move the days food across to the other esky at the start of the day meaning you'll only open your food esky once a day.
Ice is important of course. Never by the cubed party ice, you'll be lucky to get a day out of it. Block ice is much better and is usually sold alongside the cubed ice at servo's etc. These ice packs
http://www.techniice.com/dry-ice-pac...ice-packs.html are amazing. Set your freezer on it's coldest setting a few days before leaving and those things will go right down to -16 degrees or whatever your freezer is at, not just 0 degrees like ice. Another good idea is to make your own ice blocks with salt water, and again set your freezer on it's coldest setting and they will go a few degrees below 0 and last longer.
And most importantly - have fun!