Advice Refinance or Sell 1031 for duplex closer to home

Hello- We own a house that we have rented successfully in DC for 15 years. We did a cash-out refinance several years ago, but still have equity- value is 900K and we owe 280K (30 years loan) 20 years to go to pay off. We are considering buying a duplex (1M) as a rental closer to our home near a beach with the idea of renting one unit long term tenants to the other as a short term vacation rental. The house is DC has an amazing location and I just have a strong feeling it is the kind of property you hold on to. (Near two college campuses, backs a forest, strong schools, safe, close to downtown etc). As we consider the options for financing a new investment duplex - does anyone have any experience or advice with this scenario?  I would be interested to hear if anyone else held on to a single-family home and refinanced to buy a multiunit or if the most common recommendation is to sell and do a 1031 exchange. I know it is hard with so few details- but any comments are welcome. Thanks!