Back up certain services, restore after tear down and rebuild

Hi, I am doing a tear down of my network soon. I am hoping to find some advice on how I should approach this. Firstly, I have to take my domain controller and move my active directory and DNS somewhere, on another server perhaps. Can somone layout this solution? Secondly, the only other critical service that I have to deal with is my exchange box. It is running exchange 2003, and there has to be a way to back it all up and restore it later. maybe copy the exchange folder and replace it after the fresh install of the OS, or installing exchange on another box and moving the accounts, and then the accounts back after rebuilding the box? The last portion, that might be a little more difficult to explain is my VPN/routing box. I was wondering if there was a way to back up a windows 2000 server, in respect to routing configuration and general setup , without doing the normal upgrade. Reason being, I keep getting error (blue screen of death for some reason) during the setup. Any advice on any issue would be appreciated, thanks!