Investors & landlords

The cost basis for the property would be the full amount the aunt paid for it 1974; when she addied your wife as a joint tenant, she was making a gift and your wife's basis would have been what the aunt paid for the property.

You cannot include any property taxes paid over the years as part of the cost basis. 

There is no special way or place to enter the sale of land in TurboTax. It is the sale of Stocks, Mutual Funds Bonds and Other ("Other" includes land). 

See the attached screenshot to show how this would look: