the interior rear quarter trim pane is a bit more involved:
*remove the lower seat (pushed into plastic receivers) - easy to R&I but you have to pull hard to get it out
*then the rear seat back must be unbolted and removed to allow removing the trim panels. The sill trim must be removed to access the screw that holds the end of that down.
The trim panels are held in with metal spring clips - they're tight, so you have to work in sections to pull them free.