My kids were small for thier ages so the issue was their ability to walk more than my ability to carry them. It was a long slow process. At two years old I encouraged them to walk a lot -just took them out of the carrier and let them do small portions. By 5 years old they could walk very well and carry a small backpack. My kids were not too keen on going uphill and did better on flat trails. My little granddaughter is now two and would walk up to a mile at 1 1/2 years! 2 year olds certainly have the energy to walk sevaral miles, they just do not see any reason to walk in a straight line when every rock on the way is something to play with.