I did this same project a few years ago. Because I'm in a similar boat physically as you are, I hired out the whole thing, which wasn't cheap ($13,000 CD; I live about an hour away from you) for a Barkman stone patio, 2 raised garden beds and some smaller beds around the patio, dirt included. Expensive, but well worth it to me. Now I really enjoy my yard. To do it more cheaply, I would actually do the opposite of what others have recommended. I would contract out the bobcat part, as they will be able to grade it properly, and get them to put down the sand base too. Then you can put in stones as you have time and cash. If you decide to do the digging yourself, make sure you get the lines marked first - you don't want explosions!