For a quick analysis, I'd assume a 35 to 40% expense ratio. ((330x12)x43)x.6 = $102k. your offer should be around $1M.
Put together your expense list based on how you would run the park: One of your larger expenses will be taxes so call the local assessor and find out what the property and pohs tax bill is (ask them how they calculate the tax bill and if there is a possibility that it could increase based on the purchase price of the park. Also ask them if the taxes will be increasing anytime in the near future.. they typically assess properties every few years). Then mgmt fees (payroll, etc), insurance, utilities, trash, mowing, business trips, llc fees, license fees, estimated repair/maintenance, etc.. Use the more exact expense number in place of the .6 to get a more accurate offer price.