Research the area you will be hiking and find out what others do. Some trails offer drinkable water along the trail which eliminates the hassle of carrying all your water (the heaviest need). After that figure out what supplies you will need including a small first aid kit (homemade ok) and other supplies. Next food supplies: nuts, beef jerky, dried fruit, and something sweet like gummy bears. You could also look into dehydrated meals for backpacking. They probably sell them at your local Walmart. The food required during a trip like this may be more points than you normally consume, but the short duration and increased activity will balance that out.