Maguire's wax has cleaning compounds less aggressive than normal automotive rubbing componds. The grit varies by bottle number. Most stores carry them. They also make plastic polishes, but those are less commonly seen. Contact them for a distributor.
I'd skip,the wheel, and for sure it's compounds, till last resort.
I've had good luck with toothpaste for a light wheel polish at times. Yep, "Brightens your enamel" 
Stick to just the roof or bed to test. If all fails, go two tone. Recall the black or white truck roofs? Wood beds? Bed liner black? 
