Keeping the van cool

So how do we do this then. Off next week to south France and seen the forecast - it is going to be hot!!

With having 2 mini's it is going to be important that we keep the van cool. So blinds shut, windows slightly open to create a breeze, Extractor fan on blow.

Any other ideas, or has anyone used one of these:

http://tiny.cc/d43khw

Looks like it will be better than a fan that simply moves warm air around!!