We have two teens and a 38lb toddler and the teens are keen to walk up Snowdon this summer. I have a good toddler sling and we walk a lot. The train only goes 3/4 of the way up in August. We could walk up 3/4 of the way up with toddler and get the train back down while teens and dh walk to the summit. Does this sound doable? Crazy? Any good/bad experiences?