Washed ours on Monday before putting indoors for 7 months of storage. Will wash & wax before hitting the road next year.
Once on the road, well, it depends. Will never miss a chance to wash if allowed in a CG. We actually make an effort to visit such CGs if they are along our route. If there is a good chance of getting dirty right away then, why bother? Alaska is such a place. You are going to look like you have been mudding. Opportunities for a wash are rare.
It is nice to be clean but it is not worth being anal over.