Amanda,
First let me state that I am NOT an attorney and do not represent my opinion to be the law...
The estate should have listed a market value to all assets and that will be your base price for the inherited parcel(s). You will need to use that valuation as the base, whatever price you receive as the current value and your capital gains tax liability.
Lastly, my experience has been, whatever price you are offered by an unsolicited offer, is usually 50 - 70 percent of the actual value.
Good luck with the transaction.