If the holding of the purchased land is short-term, meaning held for less than a year, you can break this down into two separate sales, since the inherited land will have a long-term holding period.
If it's all long term, you can just use the method as purchased and choose various as the date acquired, then you will choose that it's all long-term. The only point of using inherited is to establish that it's a long-term holding, which is true or all inherited assets, regardless of the date inherited.
