Well, if you've been working on it for six months then you've probably learned about as much as I can tell you. No real trickery with these bikes, there pretty wrench friendly
I would suggest addressing that leaky head gasket issue though before it gets worse. This can be done in frame, and I'm guessing the white smoke is from leaky valve seals.
Bad valve seals tend to leak oil into the cylinder when the engine is not running. This is why when you first start it, it will smoke and go away. Rings on the other hand (Poor compression) will tend to continue to smoke after the engine is started and often, get worse as the oil thins out.
When you change the head gasket, have the head serviced.. seat the valves and install new valve seals and that should solve those two issues
Matt.