Oh, I just went through that headache changing out the water-pump, the T-stat, all the hoses, gaskets, radiator and the dumb fan-clutch.
As for that little hose atop of the water pump, yes, it's a bear to fight with to get it on right.
As for things leaking, I think the majority of time was trying to clean off the old gaskets from the engine parts to prevent leaks from happening. This is key to a good cooling system rebuild. I have a thread here that shows how nasty those old gaskets were and the scrapping (but carefully) to remove the cruddy old stuff.
I feel your pain of having that leak back there. It takes time to tear things apart to get to it all. That's the reason why it took me, a fairly decent garage mechanic 10 hours to do the job for everything. Why go back to re-fix something a second time.