You don't need the Pentaho Server to schedule the execution of jobs and transformations.
You can work with files, not the Pentaho Repository (a better option in my opinion, as you can have a git repository with version control for your jobs and transformations), and use the SO tool in your server (cron with Linux, whatever you have available in your case) to schedule the execution of jobs (using kitchen.sh/bat) and transformations (using pan.sh/bat) or set up the carte server (I don't use it, so I don't know how it works, look for information about it)
WebSpoon is quite stable and some people are already using it in production, take a look at it.
Regards