Some experiences I had that may help you out:
Tried direct audio from a 172 into a audio recorder, way overdriven and no clear audio.
Tried audio into a homemade resistor cable made from instructions online. No clarity, didn't work well.
Tried a y-splitter with the above cable in a 152. LOST ALL AUDIO ON TAKEOFF! Knew ATC was going to give me over to departure soon, had girlfriend hold the climb while I ripped out y-splitter (you'll remember the 152 has the audio jacks behind you). Likely a loose connection in the y-splitter but may be there was some sort of interference from the homemade cable as well. Couldn't duplicate this on the ground so I suspect loose connection.
Finally settled on buying a mypilotstore cable, couldn't be happier.
http://www.mypilotstore.com/mypilotstore/sep/8650
Great length, good audio, works easy, excellent construction, built-in y-splitter. Price is a little high but it's worth it.
As for the video, look into either mounting a camera on your headset or those suction cup mounts. I would spend a lot of time experimenting in the plane on the ground beforehand. I spent about 4 flights fiddling with things until I got it right and should have really done a lot of that on the ground.
Also, remember that if you're on a flight plan then flightaware may have your track. If you were talking to ATC then you may be able to find audio archives of you and ATC on liveatc.