REI Makes a nice pack for dogs. Indy has one but don't clip your leash to it. If you want one you can clip the leash to try a ruffwear.
Additionally…watch the weight, remember that water weighs 4lbs per litre so you want to be careful giving them water. We usually have Indy carry his food, treats, a sweater or jacket, and a toy. And then we carry it when he gets tired.
We also always make sure that he SEES the treats come out of the pack so he knows he is working for a reason.