There are multiple ways to mirror the Web pages.
You can retrieve the formatted files from a FreeBSD CVSup server using the application net/cvsup. The file /usr/share/examples/cvsup/www-supfile contains an example CVSup configuration file for web mirrors.
You can download the web site source code from any FreeBSD FTP server using your favorite ftp mirror tool. Keep in mind that you have to build these sources before publishing them. Start mirroring at ftp://ftp.FreeBSD.org/pub/FreeBSD/FreeBSD-current/www.