Some decent shoes for hiking, boots would be best, no flip flops.
Look and see what the weather is supposed to be like for those days. Pack at least light jacket if the weather is good, just in case of wind or rain.
Sunscreen is a must if you plan on spending large amounts of time in the sun, bug spray would also be a good idea.
The basics.
-Tent (if needed)
-Sleeping bag
-Pillow
-Food, snacks as well.
-Basic first aid kit
-Water bottle
-Toilette paper if none is provided.
-Trash bags (can double as a poncho with the select holes)
-Appropriate amount of clothes for three days (including socks and undies)
- For the dance, a simple dress and some flip flops would probably work well.