App for changing between a work and private mode
I would go for ControlPlane which is location-aware or can change state depending on what devices are plugged in.

You will then need to configure it with a work location and a private or home location.

Things like launching multiple apps would be firstly set up in Automator and saved as a double-clickable script. 

For example, I have one that launches Safari and opens a number of websites, then launches iTerm.

You would get ControlPlane to run this script when it detects the stage change.