>>>>I checked the coolant and when I opened the reservoir it came bubbling
out not steaming, but kind of flushing out. I quickly closed it again and
screwed the lid back on with no trouble, so there wasn't a whole lot of
pressure there.<<<<

Another thing bro!
Don't ever remove the expansion tank pressure cap!!!!!!! when the engine is
hot, this cap is like a radiator cap, kind a stupid to do so!!!!!

If you have no pressure wile removing this cap when the engine is hot you
have a non-pressurise coolant system that will result in a overheating
especially at freeway speed. Check that temp gauge over 55mph.

Have a pressure test done:
http://www.benplace.com/pressure_test.htm

Leak / loss of pressure can be internal or external.

Most common external coolant lost in order:
-Expansion tank cap
-Expansion tank (Crack)
-Front and rear heater core (Easy fix on the road with clamp blocking the flow)
-Thermostat housing (Seal, bleeder screw, crack in body, bad clamp)
-Rusty metal cooling line
-Front rad bleeding screw / front rad
-Water pump
-Heads studs leaking
-Cooling hoses (mostly at junction, but VW hoses are very good)

Diagnostic of a external coolant lost:
-Coolant lost under the van
-Coolant corrosion at hoses junction, head gasket, head stud,

Internal lost:
-Head cracks, can be oil into combustion chamber (Black/blue smoke), coolant
in combustion chamber (White smoke), coolant into oil, oil into coolant.
-Bad seal at top and/or bottom end of cylinders sleeve
-Faulty water pump

Diagnostic of internal leak:
-Oil going into the cooling system (Mostly when engine is cold). Coolant
rise slightly with a brownish color
-Coolant going into the oil (Mostly when engine is hot). Oil level rising
with coolant color/smell in it.

High temp other problem:
-Bad thermostat
-Clogged frond rad
-Faulty rad fan or sender
-Bad water pump
-Pited mating surface where water pump is.

Damn, this is why it is call a wasser leaker.

Cheers, Ben (Back from FL)
http://www.benplace.com/