I need to replace speakers installed in front doors and the Vanagon radio.  Before I mess things up, are there any tips on what to expect when removing inside door panels?  They appear to be made of cardboard and has warped a little with time.  Any special tool I may need?

Also will any after-market CD/radio (1 DIN) plug in without my needing a wiring diagram?  I don't have the Vanagon manual yet.

Lastly, any trick to getting at the rear speakers, in case I need to replace the wires back there?

Thanks!
-g