I am fond of the osprey packs myself, but a 68L model is overkill. My first walk, I used an Osprey Kestrel 48. Very comfortable unless it was a hot day, and roomy. Second walk, I downsized to an Osprey Kestrel 38L. Still comfortable unless it was hot, but a snug fit on the gear. Both the Kestrels suffer from putting the water bladder in the small of my back, so there is no airflow there. So the third walk, I took the Osprey Exos 46, which is the lightest of the three, has the water bladder sleeve inside - preserving the airflow across my back. I strongly recommend the Exos 46. Unlike the Kestrel models, it is not adjustable for torso length, so be sure to get measured and check the sizing. It is a very sturdy pack, surviving all sorts of mistreatment.