There's a recent Samba thread about this, and it links to a second thread that is said to be more complete.  Consensus seems to be that you try short rides first to acclimate the critter to the van.  People do it, while others recommend you not even attempt it.  We took our dog to Mammoth Cave a couple of years back where she got to meet a cat traveling in a Sprinter.  Good luck!
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Stephen 

    On Monday, February 15, 2016 6:35 PM, JonVO <jondvo@GMAIL.COM> wrote:
 

 If the cat is ok with a  carrier, might help with the "strangeness" on
the road - a safe place to be.  Cats travel poorly perhaps because they
never go for rides?  We have two cats, but road trips with them are
limited to the vet.
Jon

On 2/15/2016 4:12 PM, Dennis Jowell wrote:
> Has anyone  been able to figure out how to travel with a large 20 lb. male Maine Coon cat in a Westy? We are planning a trip up the Alaskan highway in the spring before haying starts. I think the trip will take at least 6 weeks from Vermont and don't want to leave our cat with someone for that length of time. One thought was to buy a big Sprinter ($$$ ouch!) that doesn't seem very practical. lol
> Any ideas from the list would be great
>
> Dennis Jowell
> Scotch Hollow Farm
> Newbury, Vermont