I really don't want to sound negative, etc., but ah, while it's understandable one couldn't ride with a child in a trailer because of all of the above things mentioned, what about just continuing riding alone, even if it's for short jaunts? While long rides and regular group stuff might be out for awhile, regular exercise is one thing that keeps away post partum depression and helps a mom keep her sanity and self-identity. Although I didn't ride when my kids were babies and young children, I did go to the gym 6 days a week. I was back there 3 weeks postpartum with both of them; it was my escape, if only for a little over an hour.
I know everyone's different, but I made a vow not to let having kids turn me into someone I wasn't. I know it sounds selfish to some, but I had a lot of experience taking care of babies and kids, as well as a few years of teaching experience when i had my first child, so I had a pretty clear idea of baby "stuff." DH and I made the decision that our relationship always came first in the family, and together, we would deal with the kid stuff. This worked for us, as we each maintained our lives apart from the family, but we had lots of fun while they grew up. I do sincerely regret that we didn't do the outdoor stuff with them, although all 4 of us developed these types of interests later. Both of my kids are awesome endurance type athletes as adults and enjoy hiking, camping, and swimming.
I just wish that I had strapped them into a backpack and gone hiking in AZ, instead of getting a sitter and going to the gym! Doing this kind of stuff just wasn't in my head, and I really wish it had been.
I just don't like it when prospective parents think that their life has to be over...