I'm keen on utilizing social media, and I'm sure that it can be done without paid for promotions. 

Tenants pay utilities.

I think it is pretty obvious sub-metering utilities is one way to significantly increase a park's profitability. 

That’ll satisfy the 25% down payment but you’ll have closing costs, escrow account deposits, first year’s insurance premium, utility deposits, $ for needed upfront capX plus reserves.

Add on insurance ($130 according to Realtor.com) and property taxes ($340/month per this online calculator) and you're at $3,105. 

So should I cough up that cash for the piece of having a solid lease from an attorney or can I save that hard earned money and just use the best one I find online?

Reviews go a long way.If this is a rental, are you going to charge a monthly access fee for the solar in addition to rent, and let them handle the utility bill, or are you going to cover all utilities?

The safe harbor applies to amounts paid during the tax year to acquire or produce what the regs call a “unit of property” (UOP), you must meet these requirements: (1) at the beginning of the tax year, the taxpayer has written accounting procedures treating as an expense for non-tax purposes amounts paid for property costing less than a specified dollar amount (which will be 2500 for you), or with an economic useful life of 12 months or less;.(2) the taxpayer treats the amount paid for the property as an expense on its books and records in accordance with its accounting procedures. ( do this on your bookkeeping software or whatever you utilize)(3) the amount paid for the UOP doesn't exceed $2,500. as substantiated by invoice.Note: The cost for the Unit of Property includes additional costs (for example, delivery fees, installation services, or similar costs) if these additional costs are included on the same invoice with the tangible property.Eg:A purchases 100 printers at $500 each for a total cost of $500,000 as indicated by the invoice.

If you start working with an account they should be able to put you on their wholesale plan and save you a little money if you buy the online version of Quickbooks.

If thousand of apartments come on line with 3 miles of each other all at the same time then it is going to be hard to maintain <4% vacancy rates.