past Events showing not working right for me on home page widget
The original module update to continue showing events after the start time was for users who might still be traveling to the event, so it was only for an hour or two. It then got extended to days, probably as a result of your request? Can't remember So its easy to extend that by a few more days, as you request, but that would need to be done within the module. There isn't a template for it.
As you suggest, ideally, this would be an option per event but that isn't compliant with the way Jamroom works as searching and listing of events would be compromised. I'll get the module updated with the extra days you ask for.