Mausberry car switch hookup to my Tacoma

Hello,
I am looking to hook up a raspberry pi computer to my Tacoma and I purchased a mausberry switch to bring it down gracefully when I turn my truck off. Mausberry's instructions are as follows:

Black wire to ground.
Yellow wire to constant +12V/battery source.
Red wire to ignitition/accessory/switched +12V source.

...I'm somewhat hesitant to start hacking into my truck's wiring, especially w/o a picture identifying where to start. How about the cigarette lighter? Is there a minimally invasive way to get the power I need without destroying my truck?
Thanks for reading this!

 

Most minimally invasive way would be, in my humble opinion:

- Any of several bolts behind the dash/under the steering wheel for your ground
- a fused wire from the battery through the firewall for your constant
- an add-a-fuse for your switched 12v

What are you using the pi for? You have me intrigued, sir.

 

Hello, and thank you for the reply!
I have an OBDLink LX bluetooth adaptor and I thought it would be cool to store and plot some of the engine data for analysis and display. I'm a new Python programmer and this seems like a good project to hone my skills. I must admit that I downloaded the free phone app from OBDLink and it is so awesome it took some of the wind out of my sails!

 

Does anyone know of a "T" type adapter harness that plugs into the back of the radio and then accepts the factory radio harness so that nothing has to be cut? Something like this attached image perhaps?
Thank you!