I am lucky enough to have a big walk-in vault. All the walls are lined with "slatwall" salvaged from a retail building we bought. All the muzzle loaders are displayed horizontally on one wall section. I have a couple of safes for guns not on the wall, and change the themes of the displays every couple of years.
I had my programmer son build a temperature/ humidity control system, and keep the humidity between 25-30%, which seems to be the best compromise to keep rust away without drying the organic materials out too much.
I understand that a vault is not an option available to everyone, but it does give me a great deal of peace of mind.