Server 2003 VPN

Hi
I represent a small group of students that have been give a School@work project. This involves 3 servers, one PDC and two Child Dc’s over an ADSL VPN We want to replercate AD and DFS.
Beore we go in and set this up we want to test this in the lab, is there any way we can replercate this over our LAN as we have no ISP type setup that we are alowed to use?
We are trying to stick with L2TP/IPSec.
Thaks.
Paul