Auto schedule Ethernet to activate/inactivate

Have you tried automator ethernet toggle?

do shell script "networksetup -setnetworkserviceenabled \"Ethernet 1\" off"

... But, since your entire AppleScript is, in fact, a shell command wrapped inside a do shell script command, then I'd recommend using an Execute Shell Script action in your Automator workflow instead of an AppleScript one. Then you can simply write the command out in its naked form, which is much more sensible:

[[ "$(networksetup -getnetworkserviceenabled 'Ethernet 1')" = "Enabled" ]] \
&& networksetup -setnetworkserviceenabled 'Ethernet 1' off \
|| networksetup -setnetworkserviceenabled 'Ethernet 1' on

If this works, the AppleScript, Automator workflow, or shell script can be scheduled using Calendar, launchd or a tool like Power Manager.