Estimate value

There is a park for sale that is 4 hrs. away from home .There are 12 lot rent @85$ per lot.Tennant pays own water/sewer/trash. 5 more lots can be filled & are unoccupied at this time.The location is somewhat stagant and is approx. 15 min. from local walmart?Taxes/Insur. are low .I need help estimating value?Any suggestions are welcome.