I had never driven a van before and had to jump into a LWB Ducato to do 350 miles in a day, the biggest car I'd driving up to that point was a BMW E46 Saloon and most of my miles were largely experienced with an Aygo!
However once I was in the van, I was absolutely fine and had no issues driving it. In some respects it's actually easier to waft around in (which essentially is one of the main requirements in a van, they are designed to be easy and intuitive).
You'll constantly be aware of the fact you're not in a 3m car and as such will drive to those conditions.
It didn't help that 5 miles after I was driving I was pulled over by Police for a routine diesel check. At that point in my five years of driving I'd never been pulled once. I couldn't figure out how to get the diesel cap open!
Officer: "Do you own this van?"
Me: "No..."
Officer: "Do you drive for a living?"
Me: "No..."
Officer: "Can you open the diesel cap please?"
*Fumbling around with keys for five minutes*
Me: "... no"