Don't bother with the drain on the radiator, more trouble than it's worth, just remove the lower hose and dump it into a 5 gallon bucker, actually one of those big oil change pans works out better, I keep a bright yellow one around just for coolant in case I am going to reuse it. To get the other stuff out disconnect the two heater hoses on the engine, drain the bottom one into a quart bottle, just blow thru the top one, then use a garden hose to push some water thru, alternate between the two and don't wedge the hose in there either, the cooling system is made to work at ~16PSI, most house hoses are upwards of 50 PSI or more, you just want to get water in a back and forth motion to loosen stuff up.