But it may have just came to mind because I'm self-centered, and have thought of similar things. Your description of circumstances is akin to mine (however seeing as how I live here, there is no retirement at that age....)

But anyways, the thing that came to my mind was that you very well could be a good "big brother" to some kid out there. In my experience, a huge difference can me made in a youth's life through being an adult in their life to speak wisdom and encouragement. Local community centers or other such places may have the opportunity for such as this.

The other thing that came to mind is more "risky" or would have a higher cost. And that would be to network with the Foster Care system. Not that you would be a Foster Parent, but to be a resource for the kids who "age out". So many foster kids hit that 18 year old place, and they are ill equipped for life "outside" the system. More often then not, they are poised to fall into a life pattern which will destroy them. But since they are too old for the system (as they are "adults" ), they are often left without resources. Nor are they truly ready to venture out. At 18, I was not equipped for life without the fall-back to my parents.

Perhaps there is an opportunity there? You don't have to go out and help a whole world. By helping just one, you are making all the difference in their world.

~Jeordam

[Edit: Fix some typos, and to flesh out a few thoughts...ever so slightly]
[Edit 2: Fix an unintended smiley]