In reply to daisy may (or may not!):
Check that you have outline planning permission. That's the first thing to think of. Then remember that most pre-fab timber houses have a life-expectancy of only 60 years, which really hurts the re-sale possibility. Then (if you're still going to go ahead) get some plans written up, poss. worth getting a architect to do it if you haven't any experience of doing it yourself.
If it's in the middle of a forest, then getting water, electricity, sewage will probably be a problem, so think about septic tanks/composting waste and a grey water system for your sewage, and maybe wind/solar-electric for power, not sure about water unless there is a clean source neary that you can use. I know you said you weren't bothered about it yet, but it is quite important, esp. for planning permission, which you will have to get.
Josh.