I have a 2004 28W. I am 6'4" and weigh a fit 250. I can negotiate the commode and the shower, even though when I am in the shower it seems there is not enough room for me and the water at the same time...
It is easier to me to sit on the commode with the bathroom door open with my dainty size 14's sort of sticking out. If I do not have shoes on, I can cram half my foot under the door and sit fairly comfortably, so to speak, once I am seated, WITH the door closed. I have enough elbow room to read a magazine, but not a paper...however, our Jack Russel terrier thinks my toes a prime target sticking out under the door. He attacks them. Part of roughing it, I guess.
The shower does not have much 'swinging' room for a guy like me. If it was any smaller, it would not be workable. As it is, it is hard for me to turn 180 degrees with the shower door closed because I cannot stand upright in there. I have to tilt my head while standing, and my ear always seems to be right next to the roaring vent fan. The good news is I cannot fall in there -- there is not enough room for the trip down.
If I were to guess, people up to 6'6" would have minimal problems if you have decent flexibility and do not have a bunch of girth. Past that, you need to be skinny to make it.