For your second question, there should be a wire lanyard tucked in near or behind the rear passenger wheels and and possibly another near the front air tank.
DO NOT GO UNDER THE MH TO PULL THESE!!!! Use a long rod (like the awning rod) as the chassis will drop down considerably and fast.
Now there is a debate about whether on not you need to do this as your air system is supposed to purge the water from the system. Some people do and some never have, there is a discussion on one of the forums.
Some pull it to confirm the purge system works, others do it on a regular basis and some never do it - up to you.
They also tend to stick open and can be a real pain to close - be warned.
Chris