Some pictures are in order:
A long root from under the grass
Despite it being a lot of work, I am very glad I dug out the bed by hand. I had considered the popular method of lasagna gardening, where you just cover a bed with cardboard and organic material and hope that the bed will be useable once everything decomposes. I decided against it because I had bermuda grass that I feared could outlive the lasagna gardening method. I don't know if it would have, but those roots would have given me grief for years if I hadn't gotten them out. I also considered renting a rototiller. That would have been a waste of money. I would have had to return it in defeat after hitting root after root that it couldn't get through.
In addition to the grass, I transplanted the small shrubs in the front bed and dug up that bed. In addition to more gigantic roots, I found other surprises hiding in the front bed. These included 6 lengths of old, rusty rebar, 5 stumps, and some bricks and bits of concrete. The stumps, I believe, were from some long-gone bushes that were chopped to the ground then buried by dirt and/or mulch. I found this picture of our house from 2004 that shows big hedges in the front yard. Those didn't exist when we moved in. I believe those are the origin of the stumps I found.
Now a before/after: