FYI - It is not all that common for long term residential rental real estate to show a taxable gain. It's more common to show a loss every single year. Those losses get carried over. So your carry over losses will grow with each passing year.
When you add up the deductible rental expenses of mortgage interest, property taxes, insurance and the depreciation you are required to take by law, those four items alone are usually enough to exceed the total rental income received for the year. Include with that other allowable rental expenses such as repairs, maintenance, etc., and you're almost guaranteed to show a loss every year.
I would highly suggest you include that on your non-resident state return so as to show the loss carry over to the state. Those carry over losses usually won't be realized until the tax year you sell the property and they will then come into play to reduce your taxable gain on the sale of the property in that year of sale.
