repairs

I purchased an older home where the only recent "improvement" had been a bathroom update. I'm sure this was only done to dress it up for the sale, A very poor quality "improvement". I recently just learned how poor it really was. The bath is being vented into some "dead" attic space. The space is only accessible from an outdoor window. It has soffit vents, but as of yet, has no other venting. I am conserned about dumping all that humidity into this space. I would like to continue the vent duct to exit outside. I would rather not have to put a roof vent in b/c I hate messing with old shingles, It's usually a loosing battle for me. I would like to put a vent in the wall. MY QUESTION IS... Is there a limit to how long the duct can be? Number of turns it makes? Is it dependent on the fan's CFMs? If the quality of the other "improvements" is any judge, I'm sure the fan was the cheapest they could find, therefor probably has very low CFMs. The run will be about 20 feet with a couple sharp bends. I was going to use some flexible (vinyl or plastic ?) duct. If it matters, I live in the Northeast.

My home is a split ranch and has a basement. We were told that the basement was "stubbed for a 3/4 bath". What can I do to utilize this space? Part of the basement is finished. I see the pipe sticking out of the floor in the unfinished side. What kind of contractor do I need and how do I choose a reputable one? We will need to do most of the work ourselves but need advice on what to do first.