Nicky and I like taking our three dogs for walks in good weather, but the process was getting rather difficult due to Bengie's health problems. Bengie has occasional cases of the "gimps" and, due to his "previous life" in a chain-smoker's house and the resulting breathing issues, "poops out" very quickly on walks. We tried several ways to get around this problem, including packing a baby stroller, but finally solved it by purchasing a HoundAbout pet trailer. The HoundAbout is heavy-duty enough to manage the cracked and broken sidewalks of our neighborhood, and the cabin is large enough to accommodate two dogs if necessary. You can attach the dog inside the cabin to a leash so that he or she can't jump out. You can also attach dog leads to its sides or handlebars, allowing other dogs to walk in front of or beside the trailer and freeing one's hands for other duties (such as the inevitable poop-scoopage). In the picture below, that's Harry on the other end of the lead going off to the right.
The HoundAbout is a little pricey -- around $150 to $200 depending upon size -- but it's definitely worth it if you have an older dog that still likes to get "out and about."