Generator Shutdown Timer

I was asked on another forum about a timer to shut down an RV generator which is an Onan 4000 microquiet. The man asked about a simple timer/relay combination that would allow a time to be set that would use the stop wire from the remote panel in the trailer to shut the generator down after a set time. He explained that he did not want the generator to run all night but shut down at a set time after they went to sleep. Anyone have any ideas on this? I was thinking of a battery powered timer that closed a relay to activate the stop circuit on the generator with a bypass switch so that you could run the generator as long as you want without having to reset the timer. Any ideas on this? I am not that electronically blessed...