It seems most organizations representing a cause have annual walks where individuals and business leaders rally a team together, building enthusiasm for one morning stroll.
I propose building groups who join together for monthly, weekly, even daily strolls. Begin with a walk in your neighborhood. A neighbor may notice you walking with Jo from across the way, who decides to join in. Soon you may have a small group who are all walking monthly, weekly or everyday to build their own enthusiasm for that one day annual event. Others then may see your group and find it such a worthy thing they begin their own group that walk every evening, once a week or each month. Then others find out but can't fit a little daily exercise in and pledge to the neighborhood walkers for the worthy cause. Then one of those neighbor's brother's cousins hears about it but he lives too far away, and running the multi-national corporation takes up so much of his time that, he decides to give to his alma mater, whose research pioneer breakthrough remedies. It may not be the organization you began walking for but it could be your inspiration that starts the ball rolling. All from you walking out your door.
I could go on...
It may become a Movement-movement.