click to enlarge My house in Marshfield village was small and a century old — hardly deluxe. But when I decided to move last fall, I had a feeling I'd have no trouble selling it. I settled on an asking price of $225,000, which seemed fair for a cute but aging structure with few modern conveniences, nor space for them. But I knew that would be considered a bargain. A three-bedroom home under $350,000 is a rarity in the coveted "missing middle" category of Vermont's overheated housing market.