Hi minimarvel, I'm sure others will have ideas too but this is what we are doing. My kids are 5 and 2 btw.
I bought one of these from Amazon for about £25... basically a media player that connects to the RCA (red, white and yellow) connections in the back with the cable included and you can attach SD cards or USB sticks to it with various file types. It also fits quite nicely on its side in the gap at the back of the front seat armrest with the USB stick or SD card pointing upwards.
amazon.co.uk/dp/B004TD4O1A/ref=cm_sw_r_cp_apa_-4y1ybJA9GDV7
In terms of playback, I've found that if you save all of your media files in one folder, you can start playing the first file (make sure the engine is running when you set it up or the player restarts when the engine starts) and it will go from one media file to the next automatically (helpful if the kids can't use the remote).
The car stereo can be set to aux2 (in the settings) and then the sound plays through all speakers. You can buy infrared headphones which connect direct to the screen but my kids are a bit young yet.
I know this is all sounding too good to be true right... well a couple of extra bits...
The player doesn't come with a car charger (it's designed for the house) so I bought one of these to power it with 5v:
amazon.co.uk/dp/B01M8HJ0CY/ref=cm_sw_r_cp_apa_ckz1ybMJZEX5T
And it might have just been me but I could hear a whining sound through the speakers so I bought a ground loop isolator from Maplin to eliminate it (just connects between the player and the RCA connection).
Overall, we find that it's great to make the most of the screen and it keeps my kids entertained on long journeys. If you use the fader to send all of the sound to the back speakers, you can even have a conversation in the front
Hope this helps
Andy
P.S. I've not done sufficient posts to include links to websites so you might need to copy and paste (sorry)
