I've done the A and C, not B. That will be more complicated because of the seat belt attachments - see FSM.
On the C-pillar, there are plastic rectangular tabs that stab into rectangular holes in the body - just like on the knee bolsters - and almost always a tab breaks off. Maybe knowing that, you will be extra careful and get by without breaking it.
The b pillars need the seat belt removed if your going all the way to the floor or not so you can disconnect the seat belt from the hole in the upper pillar. The c pillars need the rear seat removed. As well as the back of the seat iirc. The all just snap off.