E350 w/7.3 Motorhome

[Robby1]

A couple of firsts. First Ford diesel (I have Dodge's) and first vehicle when you open the hood you cannot see the engine. Boy is it wedged in there.

Here's where I would like some help. 1995 E350 7.3 30' Motorhome with 18,401 miles (on the day of purchase), stored mostly inside and looks and drives like new. I have changed all the normal fluids except antifreeze. Ford says they use a pump. Any idea what kind of pump. I have spare RV pumps.
I looked at all the hoses. MAN that is a rube goldberg setup. To top it off the motorhome has a rear heater and the hot coolant runs through water heater to heat it up while driving. Therefore no idea of total amount of antifreeze (maybe around 30 qts, maybe more).

Does anyone know, if I park facing downhill, drain radiator and block, does that normaly empty most of system? I would then coast down onto the level, refill with demineraled water, warm up and back up hill, repeat and then fill with 60/40 mix. If measure fluid out I will have some idea how much to put back in.

i suppose this is a weird question, but I never ever saw a hose setup like this one. The engineer was smokin something that day!!

Robby1