Removing rear interior panels

[NSFW]

I want to put a GPS radio and Wifi in the winglet at the top of the rear door on my wagon. I suspect I might be the first to try this, but I have to ask.... does anyone here know how to remove the interior panels at the very top/rear of the cargo area, and along either side of the cargo area?

 

I did a bit of gentle tugging here and there and nothing came apart. I'm pretty sure that pulling harder will get things apart, but I'm concerned that things won't go back together if I just take the "more force" approach.

 

Any suggestions would be appreciated.