I'm building a climbing wall for my daughter, and wanted to paint a backdrop mural so that it feels like she's climbing a happy mountain (think rainbows and smiling trees). The mural will be on a primed piece of marine-grade 12mm plywood screwed into three wall studs.
I'd like the mural to stay fresh and unblemished, even though it will have a five year old clambering all over it barefooted.
Any thoughts about what pants, varnish (or some other solution) could protect it for a few years? Help greatly appreciated!