$500,000 Motorhome. Class A? or would it be a C.

Does not matter what you call it.

Just name it: "More than my budget can stand." :)

For those that can afford it, more power to ya.

Class A only parks will not let him in.

That's plenty plush when you are remote Off The Beaten Path where no other RV can go...

$500,000 won't even buy the bare chassis for a Prevost based RV.
That is not a bad price for a very low production specialized coach such as those in the article.