These are the blocks I made from a 6"X 6"X 8' piece of redwood. I made two Chocks that fit between the tires. 4 each 4x6x12" and 4 each 2x6x12". Then I attached ropes to each one of them. This actually makes life much better for carrying them about the trailer. Since they are Redwood they are real light and they seem to be pretty durable.

They all stack in a box I made of Redwood

And the box sits under the Snug-Top cover on my Pickup

I've always carried the leveling blocks in the trailer prior to our Creek Side. There is just not enough room in that little rascal. So far I've not found a place I can't level at. I do have one set of the "large Lego's" stuck in the trailer for emergencies.