Don't get too focused on cap rates and gross rent multipliers. the thing you want to focus most on is cashflow, how much cash it puts in your pocket per month.

Overhead costs typically are incremental and remain pretty constant (unless you have one property per LLC), 1 property with $3000/yr OH costs doesn't mean 2 properties will cost $6,000/yr, unlike operating expenses which are usually multiplied by however many properties you have.

Also, you will need calculate cap rate off those numbers, cash-on-cash return, Pro forma, Gross Rent Multiplier, and Debt Coverage ratio.

currently in the process of applying for mortgage Staten Island NY 10308Property cost$450,000 $90,000 down payment (20% down) $360,000 mortgage 3.7% interestClosing Cost$20,000 Construction Cost$150,000 Built in $10,000 contingency fund for construction expensesHandeling cost25,000$2,175 monthly mortgage payment multiplied by 12 monthsTotal Investment$645,000 New Project $275/square foot$855,000 $275X3100 Sqft projected sale priceBroker commision for selling$45,000 5% broker fee$825,000 $825,000 projected sale proceed minus broker commissionTotal investment$645,000 Total investmentprofits after everything$180,000 Net profit

I would pay myself the mortgage amount to save up for a investment cash, and after you have a few of those. your cashflow will multiply quickly, and allow for growing your business at a conservative rate.

I guess as a worst case scenario I can use the tax percentage from the county records and multiply that against the purchase price...but I'm being told that is not how it works in Texas.  

An easy way to remember cap would be to take the NOI and multiply by 10 to create a 10 cap and thus (in this market) USUALLY the max you'll want to pay for the park.

You take either your gross cash flow or figure out your net cash flow, multiply that by 12 (12 months) and then divide that by your all in expense. 

Multiply this percentage by the new tax basis. 

If we were not on the same page, my stress level would have been multiplied by 100.