Can I activate over the internet and then not require any further internet access?

Yes.  Set the web site to allow manual installations but not internet installations.

When installed, your protected program will still try to contact the CopyMinder web site.  It it succeeds, it will automatically activate the installation as a manual installation and not require further internet access.  If it fails to get to the CopyMinder web site then it will take them through the normal manual installation procedure.