Well stock up on alot of rubbermaid containers! Or a few nice trash cans. Try to keep as much water as you can from the original system.

If you have the new stand and sump ready and built, that of course will make things much easier. You can put the corals and fish in icechests or rubbermaids with water for the move. Move the tank to the new stand, pour the sand back in, and then add some water. Hopefully the plumbing would be done for overflow and skimmers. That will help clean up the water. Make sure you have plenty of RO water on hand for water changes!! You can insert the coral and rock almost the same day if the water is not all cloudy. When filling the tank, place a dish or tupperware container in the sand, and fill the water there. It will help prevent the water from getting all cloudy. Run some carbon too after the change over. Test for amonia, and if it does rise, be prepared for some water changes.