I setup a Tasker profile that turns off mobile data whenever Wifi is connected. With this, you could reduce everything to a single click, or no clicks.
Single Click: Turn Wifi on with widget. Once Wifi connects, Tasker automatically turns mobile data and bluetooth off. When Wifi disconnects (you move out of range, or turn Wifi off), mobile data and bluetooth are automatically turned back on.
No Click: Setup Tasker to periodically scan for nearby Wifi networks. If yours is found, turn Wifi on and turn mobile data and bluetooth off.
What is the name of the bluetooth widget that turns blue tooth on/off when in proximity to paired device ??