You could always look into Bikejoring, my guess is that it would use even more energy than biking with your dog beside you. Do a quick google search, lots comes up. Training involved, but I don't know that it would be much more than what you'll have to do to be able to bike safely with your dog anyway. I know there are a couple of people on here that do it, or at least Skijoring/mushing/canicross (I'm planning on starting some training this spring actually). You might find it really fun!