I agree with your wife. 

What would the farm rent for?  How much equipment do you have to sell? I would sell the other farm first. Why do you want to build a house at your age?  Do you live close to your kids? Maybe you should move closer to them.  How much will the government take if you sell now? What will you invest in to prevent your money from becoming worthless?  How much money do you plan to spend on living and having fun? Maybe the other small farm would be enough for the fun money and rent and government checks will be enough for living. 

 I think that selling would result in a lot more worrying about money than keeping it.  If you want to leave a lot of money to your kids you should not sell it.  Once you sell it, it is a lot more likely that you spend all of it, lose it due to bad investment or inflation.