Making Unsolicited Offers (Buying Parks)

How do you normally find out park info such as lot rent, occupancy, number of spaces, park insurance, sewer, water , park owned homes and trash without asking the park owner. Do you ask the water department for that info etc? What other resources can you use to get this info? I was just wondering so if I make an Unsolicited offer in the mail? Then I could use all that info with the formula to value it.