Using a rural mailbox for garden tool storage

I have a rural mailbox that the previous owner left that I'd love to convert for small garden tool storage. Relocating that mailbox would save me a lot of walking from backyard around the side of the house to garage every time I needed my garden trowel, my gardening gloves, bug spray, wipes,etc. I'd like to make it decorative..maybe by using stencils to creative a design. Having never used stencils before, it looks pretty simple if I get the stencil brush/brushes and follow instructions. Would I need to spray the box after I stencil it with some type of sealer? I guess it would be good to prime it first with a paint used for metal?

If anybody has done this project before and has pictures of your finished project, would you post them here so I and others can view them? Thanks!