Before you spend any money on this project, you need to do the following:
1) Look up this town on Bestplaces.net and see what the metro population (needs to be at least 10,000), median home price (needs to be at least $70,000 or so), average three-bedroom apartment rent (needs to be at least $600 or so), vacant housing % (needs to match the U.S. average) and unemployment rate (needs to be around 6%).
2) Run a test ad to see if there is any demand.
3) Get some comps on the other parks in the town (both lot rent and occupancy).
4) Run the numbers and see if the economics justify the cost.
5) Talk to the city and see if the permits are in-line to do what you're talking about.
6) Look at the realistic cap-x demands and see if you have the capital to complete this project, including bringing in all the homes.
My bet is that, once you run all these scenarios, you'll realize that this deal is not very compelling, even though you own the land free and clear. Land is cheap; infrastructure and homes are not. There are plenty of good, existing, full 30 space parks out there that can probably give you a much higher return than the project you are contemplating.