One mountain I’ve been to the top of but haven’t climbed is Pikes Peak. *My car* climbed it one time. If you climb the standard route, the Barr Trail, it’s a slog. 13 miles one way, 7,400 vertical feet elevation gained. Most people break it up into two days as there is a wonderful camping spot with showers and hot breakfasts about half way up (Barr Camp). There’s people that can clear the summit in under five hours.