SFTP servers can "advertise" themselves on a local network using Zeroconf (aka Apple Bonjour), using service type _sftp-ssh._tcp. It advertises details such as hostname, port number, and path. Then SFTP clients can find them, and display them for a user to connect to without having to type in the details manually. It would be great if WinSCP could support this.
It depends on Apple Bonjour being installed on the PC. This could be an optional dependency, or bundled in the WinSCP installation package. See:
(user installation package)