Can't help you with the first question but you might try the mailing lists. Now the other two questions I can help you. Cvsup is also used to keep your src tree up to date this would be a source supfile.
*default release=cvs tag=RELENG_6_0
*default delete use-rel-suffix
You can change the host to whatever you want, now the other thing to change if you want is the release tag, which is set to download the 6.0 release branch. The release branch is used only for security and critical bug fixes. The other branch tag "RELENG_6" is the development branch for 6.X also called Stable "FreeBSD-STABLE is our development branch from which major releases are made. Changes go into this branch at a different pace, and with the general assumption that they have first gone into FreeBSD-CURRENT for testing. This is still a development branch, however, and this means that at any given time, the sources for FreeBSD-STABLE may or may not be suitable for any particular purpose. It is simply another engineering development track, not a resource for end-users."~Freebsd Handbook. Most likely you'll want to stick with the release branch, after you cvsup your source you'll rebuild the world http://www.freebsd.org/doc/en_US.ISO...makeworld.html
. Now if you want to update your ports, portupgrade is the way to go, http://www.onlamp.com/pub/a/bsd/2003...SD_Basics.html
great how to at that link. Now there are alot of switches for portupgrade but since you use packages, I'd use the -pp command which tells portupgrade to use packages instead of compiling. Oh one other link http://www.freshports.org
great place to see all the ports for freebsd.