I commute an hour and a half each way, and have a 4 year old. My husband plays golf till dark every day.
Usually during the week, I try to ride during my lunch break. Even though the ride is short, it gets me outside and on the bike. There are some hilly areas around here so I still feel like I get a workout.
Sometimes I bring the mountain bike, and from one of the sites I work at (I travel between 3 sites) I'm only about a half hour from some good trails. On those days, I'll have him pick Andy up from daycare, and when I'm done riding I pick Andy up from the golf course and take him home.
Otherwise, I'd only get to ride on weekends too. It means bringing my bike to work every day. I used to carry my folding bike inside the car- that way it was always available. Now I either have the hybrid or the mountain bike on the back of the car and I'm ready to ride any time I can manage it.
You might be able to get someone to watch your kids right after school and you could ride after work?
vickie