In terms of modifying the house it depends on your local market. The general observation is that something making the house "special" tends to drive the price up rather than down. E.g., radiant heating via floor circulation can be seen as risky and novel, but enough people care that it tends to be profitable. Similarly with "risky" amenities like a backyard walking path. The location determines what a normal house is, so specifics vary wildly, but targeting a large enough sub-market is almost always better than "targeting" a wider market.