The trailer has been tied down by Corky's Mobile Home Transport of Pflugerville, Texas. They set anchors into the concrete pad and tied down the frame with steel ribbons. I would have run a couple of additional cables off to the side, but they said that this was enough. I guess that if I hire pros, I might as well trust them. They seemed very nice, competent and interested in doing a good job. So with their skill and a bit of luck from the universe, we won't be going to Oz any time soon.