The parcel shelf has to come out first.
1.) Remove interior side trim at C pillar (a little tricky as you slide it up and slightly rearward to clear clips.) There are some clips on the front edge also.
2.) remove rear light connection (if present) from trunk.
3.) Slide parcel shelf forward (kinda under seat belts in C pillar trim). Make sure you clear large white plastic clip on parcel shelf (visible from inside trunk).
4.)Remove black plastic boxes.
I can't remember for sure, but I "think" that I accessed the fuel level sender by just removing the rear seat back. Of course you need to remove the seat cushion to get to the screws holding the seat back
.