Have you asked yourself;
What it is you are hoping to achieve by signwriting the van?
Once you have considered this carefully, then have a rethink?
For example, can you name ten sign written vans you saw yesterday (apart from Mcdonalds etc)
Probably not as there are so many, with so much written on them :

For me I like sign written vans, so i had mine done with a logo, and the company name. Most people won't remember the telephone or web address, but I think they might just remember the name.