Since you are no longer running a version of SBS on Windows 2000 but rather 2003 the cross posting you did probably will not help much
The correct group for posting SBS 2003 questions is
microsoft.public.windows.server.sbs

 Windows 2003 Small Business Server (PDC, AD, DNS)
 Windows 2003 Server (DNS, DHCP, FS)
 With Windows XP Pro Workstations

 I just wiped the server clean which had SBS2K on it and am installing a
 trial version of SBS2003 (180 days) as a stop-gap measure while we await
 the release of SBS2008.

 How do I set back up the System Policies and User Policies for Roaming
 Profiles, Folder Redirection, etc.?

 How do I configure RADIUS on the server?

 How do I get users to be able to access their roaming "My Documents"
 folder, etc. on the second server, again once I give them access (within
 the next hour)?

 What patches do I need to add a Windows Vista laptop to the domain?

 Thanks.
 Fred

It doesn't appear that you thought this out too well. I suggest you get back
to SBS2K with the backup or image you hopefully made. Then do a swing
migration (www.sbsmigration.com) to move to SBS 2003. Then you may be
skating on thin ice planning that SBS 2008 will be released before the 180
day trial is up. For that reason its probably better to buy SBS 2003 with SA
so that you'll get SBS 2008.