Official comment
Hi David,
If it’s at all possible, connecting remotely via VPN on your notebook would be a safer way to go, so you can check in/out files as needed.
Barring that, this is much how the version control system is designed to work, with the exception of copying files. Before you'll be offline - that is, unable to connect to the central, shared repository - you should check out any files that you'll need to modify so that you can do so.
We don't support and never recommend cutting, copying or pasting files or folders outside of the software. However, if it's for some reason not possible for you to join the project with your notebook and check the files out, this should work, on the condition that no one continues working in the project from the client's PC while you're gone.
As long as you know which files you'll need, you should be able to check those out, then copy the entire working folder to your notebook - including all hidden files and folders. Keep in mind that anything you check out will be inaccessible (to check out and modify) to anyone else working in the project while you're gone. Once you get back, copying everything back to the client PC should work fine.