(A work-around for this last point would be to place the server files in your Dropbox/OneDrive/Google Drive folder (or any other cloud-hosting service's local sync folder) - this way after you shut down the server the changes to the minecraft world will be synchronized with your cloud storage, to which you can invite your friend, which will synchronize the server's files with her computer as well, enabling her to play on the world while you are offline.)