Originally Posted by FrenchFit

For us oldsters I've found (good) gym classes that target core are very efficient, and even better if you spin afterwards. If there isn't a good class, take the core routine out of a course like PX90, I've copied one over to my smartphone. Spinning is the bomb if you are on a difficult schedule, you can use 24er fitness (cheap) spin room at all crazy hours if you need to. For climbing, I found running regular 5Ks (treadmill) has made my legs and cardio a good deal stronger. I've taken one afternoon/eve a week to do a serious work-out, two hours gym work then head to the spin room where I spin for an hour before the class starts, work aggressively doing intervals, pyramids. I haven't done any long rides in a while, I have no idea how my endurance may have changed, but I do know my HR was dropped pretty dramatically and performance up hills has never been better. In a word, cross-train.