If you answered yes to all of those questions, here's a project for you:
1. List all the elderly, busy, or disabled people you know who have dogs that desperately need walking but aren't getting it. Include your friends, family, and even neighbors down the block whose names you might not know yet.
2. Get their phone numbers and start calling them. Ask them if they'd be interested in having you walk their dog a couple times a week (at no charge, of course). If you feel awkward doing this, you might say something like, "My doctor has said I need to walk more, and I thought maybe you might loan me your dog as a walking companion."
If I still lived in an urban area, I'd consider forming some sort of nonprofit organization just for this purpose. I'd form a database into which people could call and request dog-walking services, and another database for volunteers. The people requesting services would have to be screened somehow, and their needs addressed on a triage basis. I'd also utilize 4-H and Scouting, to recruit walkers from those groups and help those kids fulfill requirements for merit badges.
Exercise is the most important element in the life of a well balanced dog! The NUMBER ONE thing I prescribe more than anything else in cases of serious behavior problems is MORE STRUCTURED EXERCISE. A tired body yields a relaxed mind. And a dog with a relaxed mind is not going to get into trouble like a dog who's wound up like a top! All too often I've witnessed the heartbreak of an elderly person who must give up a beloved dog because the dog was "just too much to handle." A couple walks a week, on the end of a leash held by an eager volunteer walker, may have saved the relationship.
Got your list made yet?