First to make the camper appear less boring, you should try to give more colors to the interior. However, do not do it too much and just pick some color as accent beside the more neutral color you can use for background. You can then use the color on several items that you put inside the van and make it more beautiful.
For example, you can add items such as pillows, rugs, or throws which actually simple enough to be used inside the camper. However, those items can actually make the camper van interior decor become warmer and more inviting with the fluffy effect that they have.
Next thing that you should do is to use different curtain. This thing might sound too simple, but you will be surprised at the effect that it will bring to your interior decor. Especially since the curtain would be part of the views that you have from inside the van. Thus it is important for you to have something beautiful to frame those beautiful views you have.
Do not forget that you can always paint your camper. Yes, it might sound strange at first but you can actually apply some paint on the wall as well as on the cabinets inside the van. This is a method that you can use if you want to upgrade the camper van interior decor and make it more interesting. Here are some example to follow.
image source : pinterest.com