For value investors there may be immediate positive equity based on the difference between the net asking price and the property's market valuation, as suggested below.
Independent realty related websites estimate the value of this property as follows: Realtor.com ($1,675,200) and Zillow ($1,673,684). Note that these estimates are made prior to and, therefore, do not include the value of the addition of the new sunroom which comprises approximately 400 square feet.
A local real estate agency, for the 3rd quarter of 2018, identified the average price per square foot for luxury homes sold in Santa Fe, NM as $395. At approximately 5000 total square feet, this house and casita for-sale-by-owner could list at $1,975,000. We are asking $320/square foot. (For the year, 2018, a second source uses $374.)