Low Impact Workouts

So...at 45 years old there are a lot of things to consider when working out. Part of me wants to get huge by lifting heavy weights and the other part wants to minimize the impact on my old bones. My chiro is a fan of the latter. Anyways, I put my weight bench away during the holidays and decided to try something different. My current work out strategy goes like this; Monday I do push ups, pull ups etc. a complete body workout with minimal weights for curls, flies, tris and forearms, using just barbells. I do two sets of 15 for each muscle group, but not in a row. Tuesday I do 30 min speed walking on the treadmill. Wednesday I do Wii Fit for 30 min. mostly core workouts and balance games. Thursday I do the treadmill again. Friday I do weights unless I had to take a day off and everything slid a day. On the weekends I try to do a swim, run and indoor bike. I don't know if it is better or worse, but I think you can see how each exercise is beneficial. I guess mixing it up occasionally is the best message here. Perhaps I will feel the need to bulk up once the sweaters come off, which is soon I hope.