If I remember correctly, the crane isn't used untile the end practically. This level is hard, with good reason. It's kind of a turning point on whether or not you get to play the last two levels.
Rather than reinventing (or more accurately, rewriting) the wheel, why do you check out the followin walkthrough for some suggestions:
http://www.sinjinsolves.com/guides/munch/munchwalk.htm