Rhino liner vynil top

I have a rhino bed liner in my truck. it is 20 years old and the UV is changing the color and texture, have had a cap on it the whole time. so the light thru the glass is enough to change it.

I have seen several paint on textured tops BACK IN THE DAY...............LOL on cars that didn't have a vinyl top but owners wanted the look.

I would say this would be the best option for your wagon. Texture paint it the color of your choice.