I'm not sure your assumption that single family homes sell for more than duplexes is correct. The rental market currently is quite strong so I'd be cautious. If you were to do the conversion, it would have to be of high quality to sell well - in which case the investment may not make sense.
You are correct that some single family properties in the Central Av area have sold for $300K+. With the square footage and number of bedrooms and baths that you have it is worth exploring the possibility of converting to a single family home. To command that price you would need to thoroughly update the home - updated kitchen, updated baths, refinished hardwoods and the such will keeping some of the old home charm. Your floor plan would also need to make sense for today's lifestyle and not look like a converted duplex. You may also need to add a garage. Of course it all comes down to money. If you need more details regarding market activity in the area or a plan/cost estimate for the conversion please contact me. Thanks
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