We used to have a free standing fiberglass shower in the upstairs bath in the summer shack. It died (and I think leaked around the drain) and I had a contractor frame in a stall area, then he and the plumber installed a 3 sided fiberglass unit of standard size, which is maybe 36 or 40 inches. I don't know how many pieces it is off the top of my head. I'll check it this weekend, fyi.My guess is more than 2 pieces. The bathroom door isn't vary large. But we have had no leaks. It's been in for 7 or 8 years.

The women, especially the teenagers, complain about not having enough room to shave your legs.
So, now I'm thinking about an outdoor shower stall along the order of 4x8, with a changing area.