First, if you remove the radiator then unbolt the engine mounts you seem to be able to slide the engine forward on the frame. The flywheel is not attached to the prop shaft, it just slides out of it. Then you can remove the cam belt cover and have a decent look at the magneto, if you really want to do that - I'm not clear on why you want to. The alternator is back there too, but it is separate from the magneto and is a bit more difficult to get at.

Are you saying the oil leak is coming from the area in the yellow circle below?
[Linked Image]
And is that the bottom of the engine? I think it must be because the cutter drive belt runs vertically downward, and that's the way it seems to be going in the picture. I'm having trouble working out what the pictures mean. It would be best if you could put an arrow or circle in this diagram (using MS Paint is the easiest way) to show us where the leak is:
[Linked Image]

I think you need to wash down the engine so you can see the underside of it where you seem to be saying the leak is coming from. Bear in mind that the oil pump is right near your leak, and if its gasket is leaking, that might be the source. However I don't see yet how it would get onto the muffler.