Please don't be offended! MOST dogs are only walked once or twice a day. My girl, Ivy (who is training heavily in agility and so needs a lot of physical strength/endurance training) only gets two walks a day. Granted, the first one is a 2 mile hike, but she only gets one in the morning and a jog in the afternoon. We also do a lot of play, training, and body work at home, which are all equally as important as walks. So you see it is not the quantity but the quality that counts.

I don't believe this is an exercise issue in of itself, but I do agree that more strenuous exercise, like short bursts of top speed, will help. However, I really think you should just draw up a night schedule, stick to it, and begin locking him in the crate at night again. If you really prefer to let him sleep outside, babygate him or put an ex-pen around his crate so that he has room to pace but not roam free. This is an ex-pen: