Can I copy a Git working copy onto another machine?

Nope, it'll be fine to just copy the repo's root directory. Just make sure you get any invisible files, too, especially the .git directory (in the project's root) which contains all the config information for the repo.

You can copy it, everything is inside the .git folder and is not dependant on anything else.

It's also worth mentioning that if you have no local changes ("git status" doesn't show anything you want to keep), you can copy only the .git directory and do a "git checkout ." from the (almost-empty) repository root directory at the end.

If it's a slow link it may also be worth repacking the repository before the transfer.

The only thing I worry a little bit about is if git-svn remembers some user information that you don't want to copy to the other developers.