This is simply a new bike opportunity staring you right in the face. You go right out there and buy yourself a hard-tail mountain bike and put a kiddie seat on the back. As soon as the kid can sit up comfortably, you are outta the house, on the bike, with the short one. The wife goes back to sleep. You climb the same hills with an additional 20-30 lbs on board, thus building strength and maintaining tan lines. And you build wife-points, which, in your new-dad state, do have a half-life of about three days.
Check Thule's offerings.