First major OS upgrade and Sandbox..
 

I've been a Mac user for only 2 years, and thanks to SD, have had no problems with OS updates. Leopard will be my first OS upgrade.

I know Leopard cannot be installed in Sandbox. I have lots of programs I don't really want to reinstall. I do have a backup drive.

Is it an "archive and install" that I need to do on my main drive, then copy to Sandbox..? Then I am assuming that if that if all is not well on main drive, I can copy my Tiger backup back to main drive....