Vpierce, welcome to the forum. Your 21FBRS is the same as my Mini Lite 2109S. For just my wife and I the size works just fine. The shower is tight but doable. I haven't noticed any problem with the toilet. These units are a hobby. There will always be some improvement or "mod" that you will want to do. As JohnF said, I want to add support to the folding shelf this summer.
My "mods" so far:
Fantastic vent covers over both vents
4" topper for mattress
Winegard Wingman attachment for antenna
Winegard SensarPro signal meter
Fan in refridge
Shelf/towel rack in bathroom
Towel bars on inside of bathroom door
Bar across screen door
LED lights inside
A second battery
LED rope light under awning
The fun never ends!