I installed speakers in my old 96 corolla about two years ago maybe. I have since "traded" up to my moms 96 camry le v6 (a much nicer car all around, except i miss my ebrake

), that I recently (yesterday) put new rear speakers into. Rayray's site was a tremendous help for the Camry, but I definately remember the Corollas werent as tricky to install.
You definately dont need to remove the back seat (I never did). But really, it was so long ago I can't even remember. The rear console might just pop off.
The fronts are easy, just pop the door panel and install the new ones. The lock is kinda tricky iirc correctly.