Yep, rear seat and side panels have to come out. While you're in there, check out the condition of the top hydraulics, make sure there are no leaks and that the level is ok in the motor.
Seat base comes out with 4 bolts or screws across the front lip (some markets or years it just pulls up instead).
Seat backs come out with two bolts down low and two more up high (accessed through slits in the top well vinyl).
Side panels come out after undoing 4 or 5 screws per side. Two are hidden behind the loudspeaker grille/light panel. Just pull that off its clips and disconnect the lights. Disconnect the loudspeaker wires but leave the speakers in the side panels.
That's it, you're in. Check out the state of bodywork with regard to rust, check the seatbelt reels are clean and free.
Oh, and sort out that window regulator for goodness sake!...