The best way to clean the vent is to purchase a long, flexible dryer vent cleaner from a Big Box type store. It looks like a cleaning want, only it is flexible and typically six or so feet long. You kinda give the hose an enema.
As for the ducting, the best way to duct a dryer is to use 4 inch diameter smooth walled duct, NOT the flexible corrugated duct. However, using the sheet metal requires a bit of finesse, as it is a bit of a pain to cut. There are special fittings that allow you to make corners, or any angle for that matter, both in the horizontal and vertical planes.
A couple of tips if you put in sheet metal. Do not use screws to connect the joints, they catch lint. Use aluminum duct tape, or if you insist on cloth tape, make sure it is temperature rated, since the duct will get warm. Second, for ten dollars you can get a diverter which goes on the inside of the house. In the winter, you set the diverter to blow the warm air into the house, saves energy. There is a nylon sock over the diverter to catch stray lint. In the summer, you flip the switch, and the hot air goes outside.
There are entire web sites devoted to dryer ducting (I kid you not). Just google dryer duct installation and check it out.