Storing packages for later reinstallation or deployment

[Edward Ned Harvey]

Hey all.

I wish to download once, install many times.  I'm reading through the conf
files, man pages, mailing list archives, etc.  And I'm finding myself
confused.

In the macports.conf file, there are options:
	sources_conf
	portarchivemode
	portautoclean
	rsync_server
And in sources.conf, it specifies:
	rsync://rsync.macports.org ... blah

So the easiest way to figure this out would be ... if somebody simply tells
me how to download once, install many times.  That might make me understand
what's going on here.  But unless that happens, let me at least ask some
specific questions that might help me understand.

Why is the rsync server specified twice?  Once in the sources.conf file, and
once in macports.conf?

I assume that if I change portarchivemode to "yes" and change portautoclean
to "no" then the package files will be downloaded and not deleted from my
hard drive, right?

And if the package files are not deleted from my hard drive, and I wish to
repeat the installation on another computer (identically configured), I only
need to copy /opt/local/var/macports/packages to the new system, change the
rsync sources to file:///opt/.../packages instead of rsync://blah, and
repeat the "port install" command, right?

If my assumptions are right so far, which conf file(s) do I need to update
with the file:// url instead of the rsync:// url?

Thanks everyone for your help...