First you can try to use barndoor as a unique bathroom door which actually suitable for those who has small bathroom but still wanted to use this theme. The door is sliding to the side which then you can save room in your bathroom.
You can also create rustic vanity in your bathroom which will not only functional but also give more rustic sense to the bathroom as the vanity is one of the main items in the bathroom. But if you do not want to use vanity, you can at least use rustic countertop in your bathroom or even a rustic sink when doing rustic bathroom remodel.
If you want a nice background for your bathroom, then you can try to use barn boards in your bathroom wall which finished in rustic style. Or if you want something more solid, then you can try to use exposed stone which actually good for your bathroom wall.
For decoration, try to use natural material such as rattan, linen and many others. This natural material is suitable for rustic theme but it will also give your decoration a new layer addition which actually make it richer. The texture will also make your decoration stand out more.
Another way to bring the nature into your bathroom, you can try to put some plants in your bathroom. For better experience, try to use vines that you can try to put on your wall. Or if you want something more simple for rustic bathroom remodel, you can always put a pot of plant.
image source : pinterest.com