If you planning to do a trek in the mountains for a weekend, I think that is essential to take:
1. a map, because you need to be sure that you are in the good road.
2. a tent, because it protects you if there are any storm day.
3. A rucksack where you can put your clothes and food.
4. A boots, because it’s essential to take care yours foots!
5. A sleeping bag because you need to sleep in a comfortable space.
6. A pots and pans where you can cook your dinner!
7. A waterproof jacket for protect your body that windy, rainy or stormy days.
8. A first-aid kit because if you have some accident you need to use this material.