Need to replace a few parts....

Coming on the heels of my thread about the 2014 used Grand Designs Momentum, we do need a few parts to fix up my toy hauler to sell or trade in.

Does anyone have a good suggestion on a website? Seems easier to have these delivered to my home:

1) floor grate-- I was wearing heels one day and I took out two bars on the floor grate (heater?) so I would like to replace the whole grate cover.

2) red brake light on back of toy hauler fell off somewhere recently

3) on the sink faucet in the bathroom, the piece that holds the screen (screwes into the faucet where the water comes out) cracked and I need to replace it so water doesn't spray everywhere.

I am having a HARD time identifying the names of these parts and finding out a part number, etc.

I don't live near an RV facility... Would it be best to go to one of these places and just have someone come out and look at what things I need?

What is the trick here? I spent an hour on the Internet earlier and got nowhere...

Thanks,