Just the back and sides? Sounds like a haircut!
can't beat good sign writing on a van, it just makes you look pro.
A mate of mine had a leased van that he didnt want to get sign written so he gos some magnetic signs. They were class. He just took em off at the end of the day, and you couldnt really tell they were only stick-ons.
might be a good idea for your van sides mate.