Kelly,
I do not understand why you are multiplying the lot rent by 70. However you could look at this somewhat differently. The lot rent for 11 lots yield 41580 per year. The rent to own lots yield the same in lot rent and an additional 46200 per year is income related to the purchase. You can deal with that in several ways but the income has value.
If you use all the income generated I believe it is 129,360. If you subtract the 41,500 in expenses you are at 87,000 for NOI on this scenario. I believe the Income from the rentals have value and that when they finally pay the home off you will make up some of that by a reduced expense ratio. Cash flow will not be hit as much as you might expect.
Based on just the numbers without knowing the condition of the park structure and the ability to replace tenants, I think think your method is undervaluing it. Also if the casino becomes reality there are many low wage jobs created just 15 miles away. Something to consider.