This is the model we are loosely basing your pallet play structure on. The latter images are ideas for the structure you had mentioned in our meeting of possible ad-on activities for the children, like:

...a table with a cutout hole for metal bowls to play in.

Small shelving can be added in the structure for toys and tools and so on.

This is a rather "large" example, but I can build a smaller version of this and use a part of the structure wall for hooks. And it would be fun to have the small table with multiple bowls of different sizes the children can play in.

We both liked the idea of having a space "under" a structure on stilts, but this is a cool idea to have a small lofted space for the children to climb into...like a lookout tower.  This structure and how it's positioned to the brick wall is similar to where we're putting the structure next to the fence. Building a narrow step-ramp up to the lofted space would be cool! Just an idea!

This is just an added inspiration I thought was cool. But we can figure out these details after the structure is built.  I just think it's a cool way to store little items in tandem with it functioning as a little desk.