Question: How might I go about running a JNLP app on a machine that has no Internet access? Is there a way to copy the app's files from a machine where the app has already been downloaded and run?

Answer: 
A better solution is to request a .jar file download that you can run with `java -jar program.jar` because the files that are stored after the launch of the .jnlp isn't really "readable", you will find that resources and classes names are somewhat obfuscated.
A project named [jnlpdownloader](http://code.google.com/p/jnlpdownloader/) does this task, download from the jnlp all dependencies and creates executables.