How would you wire an electric digital timer so that it will power on a dvd player which in turn would auto-play the dvd?

You must somehow by-pass the toggle function of the power button on the dvd player.

The problem you will run into is the menu on the DVD. I am sure you could get it to power up and start the disc, but it will get to the menu and stay there. 1 point goes to VHS!

How would you wire an electric digital timer so that it will power on a dvd player which in turn would auto-play the dvd?

You must somehow by-pass the toggle function of the power button on the dvd player.
I know you wanted something simple, but here is something complex.

IR Trans - Technical Information - IRTrans Ethernet (http://www.irtrans.de/en/technicalinfo/lancontrol-xl.php)

You can find other timer devices that will send IR codes. Some might be X-10 based. You can look around.

Thirty years ago, I needed to do a similar thing. I wanted to "hit" a momentary off button of an audio processor when my audio system turned off from a timer. My interface was an opto FET and an current regulator in the processor. This allowed a pulse from about 5V to 32 V to operate the button. A little electronics design in the timer and it worked fine to this day.

If you only have to hit a button once, there is an X-10 module that will output a dry contact and there are many X-10 sequencers out there.

If you don't want to modify the DVD player, you can modify a universal IR remote or find an IR remote with timer capabilities.

Ended up buying a commercial dvd player with a programmable play sequence.

Correction... it was not a programmable play sequence, but a programmable power on sequence.

Had to search long and hard for it, but they are out there and it worked great.