Differences in market appraisal- help?

My fiance inherited some land from his father, and he is wanting to sell it. We have contacted a few real estate agents in the area and have received appraisals from two of them, but there are pretty big differences in the estimates they have quoted us.

One has given an estimate of $65,000-$70,000 and has said it will be offered at $70,000.
The other has given an estimate of $85,000-$95,000 and has said they will list it at $99,000.

The property itself is just a block of vacant bush land, it hasn’t got power or fencing etc. and it is located in a very remote area (Northern NSW, Australia- between Tenterfield and Casino). We aren’t expecting much from the sale, and are hoping that it will be a quick sale (his father died over 5 years ago and it’s taken this long to get everything finalised as far as deeds and just want it to be over and done with).

Due to the location there aren’t many real estate agents who we could use- perhaps one more. We’re worried about the differences in the appraisals and the quality of the information that has been provided to us. Whilst the people quoting $99,000 have sent us a folio with detailed information about other sales etc. The other people who quoted $70,000 have just sent us a contract (Sales Inspection Report and Exclusive Agency Agreement) with none of the accompanying information that we expected.

What should we do? Why is there such a large discrepancy between the two appraisals?
The last time a property sold in the immediate vicinity (the lots around the property) was in 2005- two were sold the same time. One was 48.58ha and had some sheds- it sold for $80,000. The other was 40.37ha and sold for $50,000.
Our property is 40.35H

There is currently one other property listed in the same town area- it is 48.56H with 3 dams and some fencing- it is listed with the $70,000 contract people- but I think it has been there for quite some time and if I am right and it is the property I remember looking at over a year and a half ago on the internet- it has been listed for a long long long period of time.