If you want an accurate value of the property I strongly recommend having a licensed appraiser look at the property for you. Realtors like myself can provide you a fair market value for the property based upon other similar property in the area that have sold as well as any that may be on the market currently.. Is any of the acreage in a flood zone? If so this will have an effect on the value. In order to arrive at the fair market value of the property with some degree of accracy, you are going to have to get someone to look at the property. I recommend having one of the Realtors who specialize in land tracts or an appraiser provide you with an appraisal on the property if you want an accurate value for the property.