Don't know a whole lot about what grows in your climate, but what about some bamboo to block the trailer? Bamboo is very invasive, but being confined in a raised bed it has to stay in that area.

Arbor vitae grows quickly and is tall -- and likes the sun. I'd plant a wall of them to block what you don't want to see.

definitely no on the bamboo. I've seen it go under driveways, that little planter and the fence aren't even going to slow it down.