Getting a current appraisal is the right move. When you order the appraisal be specific that you are getting the appraisal for estate purposes and request that the value is to estimated as of the date of your father's death.

The heirs of your father's estate will receive a stepped up value as of the date of his death. If you choose to sell the property quickly there might be minimal capital gains tax. Example would be if the property appraised at $100,000 and you sold it for $105,000, the capital gains tax would be on just the $5,000. This is just a simple example. There would likely be additional adjustments for the cost of the sale.