Ford Repair: Blown head gasket or frost plug problem?, oil pressure gauge, blown head gasket

Question
Yesterday, my 1992 much loved FORD Aerostar starting blowing smoke out the rear... the oil pressure gauge was fine, and check oil light didn't come on. I was about a 30 mins from home with no alternative but to drive it home. The temperature gauge did not go up.  When I did pull in my driveway and turned the engine off, there was a brief puff of smoke/steam from under the hood. It did smell like hot oil.  The back window has an oily smear on it...
Today I checked the radiator and it was empty and on the advice of someone I filled it with water, the van starts and runs... but today the Check Oil light came on when I started it.  The oil is really dirty.... but is above the empty level and below the fill level...usually I would add a liter about now.  She doesn't burn oil, has been months since she has needed oil.  She doesn't have that many kilometers on her only 142,000.  I am on disability, and have no money.... can you give me an educated guess about what is going on?  I have had to replace the frost plug in her about 9 years ago, but haven't had problems since then.

Answer
you really need to find out what fluid leakage is underneath causing the smoke-check oil light on aerostar usually means at least one quart low of oil which wouldn't cause any smoke-if radiator was empty could be caused by leaking hose/radiator/freeze plug/intake gaskets etc. i realize you don't have a lot of money but you could damage your van driving like that-there should be a minimal charge to look at it if any charge at all sometimes customers attitude goes a long way toward checkout charges at my shop. what i mean is if you come in tell me what the problem your having is and give me some time i won't charge anything to look at it but if you come in insisting i stop what i'm doing and look at it now there will be a charge guaranteed. but please have someone look at it instead of keep driving it like that.