I quit carrying son #1 at 3 1/2. I got tired of being kicked in the kidneys, poked in the ears, hair pulled and most of all his heavy bowling ball butt on my back

I am back to square one now and face years of carrying son #2 but I can tell you that at 4 years you can train them quickly to hike Yes, you won't go as fast but you can realistically expect them to give you at least 4 miles after a couple hikes. I had son #1 hiking 10 mile days by 4 1/2 - which granted not many kids want to do, but with training and lots of treats can do