yeah, it's an old house the channels in the floor are only a couple inches wide..
i already have a dryer vent in one of the basement windows, and have been planning on doing just what you did with a fan.. but the only time i spend down the basement is on the AP system, if i spend lots of time down there, i end up with a bunch of bumps on my head, because the ceiling is lower than 6' in many places..
gonna try to get some more pics over the next week or two