I always forget the exact command and URL to get a copy of the FreeBSD source using subversion. So here it is, for my convenience and yours!
To get Release 11.1 (includes bugfix and security patches; keeps you at 11.1):
cd /usr svnlite co svn://svn.freebsd.org/base/releng/11.1 src
To get Stable 11 (includes general updates; updates you to the latest 11.x):
cd /usr svnlite co svn://svn.freebsd.org/base/stable/11 src
To get ports:
cd /usr rm -r /usr/ports svnlite co svn://svn.freebsd.org/ports/head ports
Older versions of FreeBSD might not have svnlite in base. In that case install svn and use that instead.