Well after all my original ideas and attempts at pre-planning, we won't be doing the full rush-around-the-USA bit after all, not enough time. I do thank you all for the advice. In Oz, we get used to travelling long distances in reasonably short times. After the lazy two weeks in Floida, it will now be a quick trip by car from Miami to Mobile to New Orleans, then by air to Rapid City. From there we hope to pick up an RV and after a visit to Mt Rushmore and Crazy Horse, motor down through the mountains to the areas of Bryce Canyon, Monument valley, Antelope Canyon, and on the vegas and LA, as originally planned. Hopefully we can get the vehicle we prefer in Rapid City, but I am still looking. Travelling by RV in the first weeks of June should make for a relatively easy trip, with not as many (other) RV's on the road as during the spring/summer rush hour.