This is a naive question, I'm sure. I suspect it would require some kind of server installation on my local computer...

Q: Is there an easy way of working/designing zenphoto/zenpage application off-line? i.e. on my local computer, when I have no access to the server, and then when I'm done, uploading the whole thing to the server.

Cheers!

Do a Google search for XAMPP, WAMP or MAMP. These are complete packages that come with installers. There are many more though.