How can I tell how much my house is really worth?

Okay, my husband is a contractor who has totally remodeled this old house we live in. It's 100+ years old and used to be a boarding house in the old days. He made his own hardwood flooring from oak and put it in this house (the original hardwood flooring was worn thin and broken up). We have a complete privacy fence around nearly an acre. A garage separate from the house. My husband's workshop/garage is also a separate building. A concrete parking lot in the back for his work-vehicles. Central heat & air units and gas heat as well. 8 fireplaces, six bedrooms. New windows, roof, and siding. He says our property is worth close to 200,000, but I'm not so sure. We live in a very rural area where property value is low (an hour from any town in any direction we go). So how do I go about figuring how much this place is really worth? There is not a single house around here that I can compare this place to, all the other old historic homes were pretty much abandoned and left to rot.