A large sturdy canvas travel bag with side opening (zipper). It is better to have only one large bag, rather than two small ones.
The full bag must not exceed 15 kg because it travels on the carriers’ backs. No need to load the luggage with non-essential things during the walks. You can leave some of your belongings in the vehicle or at the hotel.
For you, you only carry your daily belongings which will be very good in a small backpack (+/- 20 liters): Clothing and equipment useful during the day (camera, telephone, sweater, water bottle, hat, rainwear , sunscreen, etc.