I did some research on your 2001 Coleman Niagara Elite and found that it has 3,500 lb axles so for brake assemblies you'd want the # AKEBRK-35-SA for a new set of self adjusting brakes. Then for a hub drum you'd want the part # AKHD-545-35-EZ-K. view full answer...
I took a look at Coleman's website and they have the Phoenix Faucets RV Outdoor Shower Box item # PF266201 listed as a replacement part for the entire outdoor shower. The Replacement Shower Valve w/ Vacuum Breaker item # PF223242 would give you just the faucet for that set up.
We also have these same parts in black;
Phoenix Faucets RV Outdoor Shower Box item # PF266701
Replacement Shower Valve w/ Vacuum Breaker item # PF223701 view full answer...
Since there isn't a smaller bracket setup for the CE Smith Heavy Duty, Vertical Bunk Brackets # CE10160GA-2 best option might be to use spacers to take up the extra space and provide the tighter fit. view full answer...