There are many benefits for the seller to carry the financing.
If they want out of management - they'll do it. If not, they won't.
Show some skin in the game. If you come off as a no-money-down - recent seminar graduate, you'll get turned down.
But if you have some capital and a track record, a seller who wants to put the park behind them, will do almost everything you ask.
Be aware - some agents don't understand this type of transaction and will sabatoge the deal. They don't want to get sued if you don't perform.
Provide a fast, easy solution and the seller will follow your lead.
Keep us posted on your progress,