DIY Card Access

I am a low voltage tech and install (physical security) card access at work quiet a bit. I am familiar with many panels and readers however, without a head end/ server a conventional panel is useless. Any suggestions on how to use rfid possibly connected to an old computer connected to a usb relay board which triggers certain out puts to unlock doors turn things on/off with rfid/ prox key fobs old hotel room cards etc.? not necessarily to be used just for card access but to be configured turn on and off appliances on schedules....