Where to sell, Where to sell?

I have a project planned for this summer.
I think I'm finally going to get around to it.
It is to clean and organize my storage unit.
When the hubby and I were married, one of our first purchases was a big long old reffer trailer.
It became our storage unit.
And what a lifesaver it's been.
We started out our life together in this lovely camper.

And two years ago we upgraded to this trailer house.

So that storage unit has been wonderful, I've actually had a place for a deep freeze, food storage, basic storage, ect.
But it also has a bunch of unneeded stuff in it.
So my mission is to go through it and organize it.
So my question for you is...
What's the best way to try and sell the stuff before I just donate it?
Craigslist?
Garage Sale?
KSL?
Facebook?
Any other suggestions?

Thanks for your help!
Me