When I was pregnant with my first child, a friend told me my life was about to drastically change and that I would not be able to do anything that I was currently doing. Her experience was that once a child came into your life, biking, hiking, running, etc. went right out the back door. It was at that moment that I vowed to never become a mom who "couldn't do it" because I had children.
Equipment, equipment, equipment! This is the secret. Plan now to purchase that bike turn stroller or the baby backpack. My personal favorites have been our Chariot bike trailer (we also purchased the cross-country ski attachment and jogger attachment) and my Kelty kids child carrier with sun shield. We have used these pieces of equipment through 3 children and they are still in great shape. The cost up front is a bit high, but considering how much use we have gotten out of them and how long they have lasted, it was worth every penny! Having the proper gear is the first step to adopting the mindset that family recreation is not only doable, but enjoyable for all.