Just got done installing a new water pump last weekend, so I feel your pain. I LOATHE any job involving coolant. Sticky, watery, gets everywhere, just a royal PITA. Of course, I've had to do just about every coolant-related job on this truck (hoses, radiator, thermostat, and now water pump), but not at the same time, so I've had the 'joy' of taking coolant baths more times than I'd like.
The only recommendation I have is to open the petcock slowly so you can control the flow. Full force, mine hits something in the steering linkage and makes a mess, but if I open it until just before the stream makes contact, it's much less messy. The drain blocks are another story. They're not super easy to get at, and the stream will go just about everywhere. One of these times I'm going to replace them with petcocks to try to gain some control, but I keep forgetting to buy them in advance.
Oh, and for anyone curious, just draining the system via the radiator petcock will NOT get out enough to not make a mess when removing the water pump. I drained mine the night before using just the radiator petcock, and I was thoroughly pleased that I did not make that big of mess. I figured doing it the night before would save me from having to deal with any nasty coolant the day of. Well, turns out that didn't work. Once I got the pump free, the water line was still high enough that I dumped about a half gallon or so on the driveway. I was too lazy to get underneath and remove the block drains, so instead I used an old turkey baster to remove enough coolant so that the surface would stay dry as I tried to clean it.
Mike