The head gaskets are not a high failure item if the engine has not been overheated.....on the POST 1995 3.8L windstar.
However, the head gaskets WERE high failure on the 1995 3.8L
What IS high failure, that can be misdiagnosed as a head gasket failure is failure (leaking) of the lower intake manifold gaskets.
This can be leakage into the intake....and into the cylinder(s).....which can lead to the diagnosis of head gasket failure....when it is just the lower intake manifold gaskets.
They can also leak coolant into the oil.....and even outside the engine.
My lower intake manifold gaskets had slight leakage into the cylinders......and I had some coolant show up in the oil in the samples that I sent to Blackstone Labs for testing.
FORD improved the replacement lower intake manifold gaskets, so, if done correctly, the repair should only need doing 1 time.
If the van is behaving nicely now......
I would change the oil.......top off the coolant if needed.....and monitor.
If you have a slight loss of coolant.....and no drips on the ground......I would suspect a internal coolant leak.
In any case.......
I would change the oil at no more than 3k miles and send a sample in to Blackstone Labs for testing.
They will send you a free sample kit.....and the test is not expensive.....you should know within a week of sending the sample.
They will detect coolant in the oil at a much lower level than you will be able to tell otherwise......and serious damage will be happening in the engine LONG before you will be able to detect coolant in the oil by other "eyeball" methods.
www.blackstone-labs.com