Now see that would've been ( and is ) a valid point to bring up. But yes, im confident they'll be fine. I've taken them camping before and they absolutely adore being outdoors and active, you can bring them to a fancy dinner and they'll enjoy shopping for the princess outfit but they're equally happy coming out of the woods covered in mud after a summer rainstorm. My sister isn't nearly as active/adventerous as I am so I took it upon myself to make sure the girls at least know what it's like ( and there's nothing like feeling their pride radiating off of their faces when they've overcome something they thought they couldn't do, finish a climb, make a jump, fucking outrun me in tight corners.. little shits ). That's what I want to instil, whether or not they continue these kinds of activities as they grow older/into adulthood is up to them. I've never done the route along Hadrian's Wall but according to friends who have, you won't be disappointed. It's on my list :)