Start with creating an awesome garden.
I had one friend who did this at the Senior Nutrition Center. He grew 7000 pounds of produce per year with very little time. The produce was eaten fresh that day by the seniors. Be sure to involve folks in sustaining the project. (kids, 4H, other seniors, etc..) You could probably start one of these per year. There are lots of grants for this type of thing. You can do these type of gardens at churches, daycares, schools, nursing homes, vacant lots in cities, food pantries, etc..
In the winter time adopt some of the Seniors from the Center and become their goto person for home repairs, transportation, meal prep etc..