Trevor you're talking about whats called "lonnie deals"
site for this - http://www.mobilehomeinvesting.net/
great podcast (not that many episodes yet)
You can get the lonnie scruggs books that break down the nitty gritty for a I think...50 bucks for all 3? - you'll probably also want mobile home repair books just so you have an idea (even if you do contract out the work)
You'll buy at x and sell for x+ profit and have a "note" so once they pay it off you sign over the mobile home to them.
One big thing is that on top of any payments made to you these folks are going to have move in and down payment fees so you have to think about that - do the people in this market / who would live in this park have that kind of money up front + a down payment to you?
Worst case you'll want to have whatever you're into the thing paid off by them in 10 months or less (thats the rule of thumb i've heard, not sure if its based on statistics of people trashing the things and running off) , 6 months is better and of course up front is best.
So if you got the thing for 2k and they pay you 200 a month for it that works great (sell it to them for say...5k) , but you'll run into trouble if it takes longer than 10 months to get your money back out of the deal (again, just the rule of thumb i've always heard)