advice on taking doberman trekking/hiking please?

[Girl G]

my dobe is very hyper and will run around mad off lead. I want 2 start hiking at weekends as i thought this may help him calm down and focus on us more? I want him to be able 2 carry his own food when hiking/camping but his back pack is too small, any recomendations on a comfy but sturdy back pack for him (must be waterproof)? He eats canned meat and dog meal but i will need 2 put him on dry for a hiking/camping holiday. He is a bit too thin as it is so any suggestions on what to feed. Ie puppy food for calories when trekking every day? All good advice welcome!thanks