Applications :: Create Local Mirror Of Remote Server Without Altering It?

I'm new here and hope to profit from your immense linux knowledge and of course to share my own experience where I can.

I'm in a student organization and we use a file server that runs linux. I can log in through ssh and copy using scp using login and password (no rsa/dsa keys because most users are windows users using winSCP and they're lacking in computer knowledge so we don't require them to mess around with keys)

However, I don't have network access everywhere, so I'd like to make a copy on my laptop harddisk of some of the folders I use most frequently. Note that I don't need it to copy files from my pc back to the remote server so I don't need two-way sync. Deleting the local copy every time and downloading a new full copy is not an option as we are talking about several gigabytes and the download speed is limited. Normally I would use Unison, however, this requires unison to be installed on both pc's and I can't install any software on the file server so this is not an option.

Any ideas on how to achieve this? I'm reasonable knowledgable about linux so I don't mind tinkering with some config files and using command line applications.