Hi Robt871,
A couple of thoughts come to mind.
You mentioned that you cannot put in a garden, but that you have a decent yard.
If that is the case, I would start container gardening. You can purchase/build small containers to place throughout the yard to use as a makeshift garden that are removable. If you listen to Jack's podcasts about gardening, he often refers to certain herbs that you should not plant in your garden because they are invasive. His suggestion is to container plant them near the raised beds.
Tomatoes, herbs, and a tons of other plants could be grown in containers in the back yard if you have proper sun exposure. You can even grow root crops such as potatoes, carrots, and radishes in specially built containers that are actually easier to use that raised bed gardens.
Chris, one of the other members to the site posted a nice video that shows how to plant potatoes in a very easy manner that uses a container.... You can watch the video here:
http://uk.youtube.com/watch?v=2xbUI6Y18pY&NR=1If the home has gutters and downspouts, you could easily put in a rain catch barrel by routing one of the downspouts to a large barrel. This would eliminate the need to use city water for the containers.
Good luck!