We cannot give you any advice on inheritance tax as this is a forum for income tax.
If you inherited the house by quit claim deed from the estate and then sold the house yourselves, meaning you and whoever else inherited the reminder of the property, you would owe income tax on any gain on the sale. If you already owned 25% before the sale, the cost basis on that portion would be your costs basis at the time the house was purchased.if your husband was co-owner from the beginning. (If this was a primary residence, you could write up that cost to the value at the time of passing, but I don't believe that applies to an investment property.
The other portion you inherited when your husband passed away would be valued at the time of his passing. You should probably see an attorney to help you understand the difference between income and inheritance tax. Since you no longer live in CA, they will automatically withhold an estimated amount of income tax on the sale.