I'm not retired yet, but I think that it would be a lot of fun to do volunteer work and see how I might make a difference in other peoples' lives. If you are financially set, I think it would be a lot of fun to try to create a company/small business to give people who are without work (AND WANT TO WORK) jobs and also make them part owners into the company. Then, kind of bow out and let them run their own business. Others have also said to help out the elderly or needy who cannot afford to pay you back with money, but just a simple Thank You. That, to me, sounds like a life filled with meaning and purpose.
Your question is a lot like, "What is the meaning of life?"........best answered by the one who asks the question! Where you place your time, so to do you place your heart. Whenever I get stressed about what direction to take, I get lost........so, my advice is for you to "Get lost." As odd as that might sound, it isn't such a horrible thing. Whenever I "get lost", I am forced to "find out where I am at" or in other words, "find the purpose for what direction you should take." This is a great time for you to do things that you have always wanted to do and find the purpose in doing what you always wanted to do, but maybe never had the time to do and not have to chase the dollar to do it!!
You like cubs and people need their lawns mowed, snow removed, gardens tilled, etc. so create a business that is 100% charitable where free will donations for those services are given to ....... The Cancer Society, ASPCA, The Heart Foundation, a local animal shelter, create a scholarship, etc.
When we expire, our character will be our greatest legacy that we leave behind......or at least that is the way I feel. Whatever you choose to do, I hope it keeps you active enough to provide exercise, relaxing enough to be enjoyable, meaningful enough to be remembered by others, and satisfying enough to keep you smiling!!
Congratulations upon reaching your retirement......we should all be so lucky to find ourselves facing the same question you are at this time!
Cub Cadet 123