The cleanest way to go in my opinion since you already have a working macOS 10.13 VM would be to:

• Install Xcode, the Xcode command line tools and MacPorts on your VM,
• Get a list of the ports that you have installed on your old system
• Re-install the ports in the VM

The MacPorts site has a procedure used to migrate a MacPorts installation after a major OS upgrade or from one computer to another. This procedure is found at https://trac.macports.org/wiki/Migration and includes a process of listing the installed ports on the old environment and reinstalling them on a new environment. This procedure might be useful in your use case.