How do I buy Illinois RV and get it to New York?

Unlike say CA, and maybe OR it sounds like, in IL the tags stay with the owner, not the vehicle. Now, the seller could leave the IL plates on, if he was not going to re-register them to another RV. But that's not a smart thing for him to do. I don't know if IL issues something for temporary use. They have a temporary plate for use till the permanent plates come, that much I do know.

I would drive it home but then again I like to question authority. :)