I think my '83 300CD turbo (Calif.) is showing signs of head gasket failure:
*A year ago when I flushed the cooling system, I found some (not a lot) of motor oil in the old coolant.
*A couple of weeks ago, I could actually see the exhaust for the first time (it isn't clear anymore...) - a slight whitish color.
*The exhaust smells like burning antifreeze, certainly doesn't smell like burning oil.
*I am noticing the coolant reservoir level slowly dropping and since the car isn't driven much and stays in my garage, I have found no coolant leaks in the garage.
*The 617.952 engine (original) has 242,984 miles on it.

Does this sound like a failing head gasket?

About the car...
*It is babied. Driven like 1,000 mi. a year at the most.
*The wife bought it just before it turned four years old (just over 20 years ago!) w/only 39,113 miles on it! This is one sentimental car to her!
*The timing chain and tensioner were replaced about 67k miles ago.
*Most everything works, a few body paint imperfections, it needs some front end work (track rod mounts).

If I have the head rebuilt...
*Have the valve guides and seals replaced?
*Wire brush the valves and grind the seats?
*Pressure check the head?
*Check the head for cracks and flatness?

How much should I expect to pay for this work (I'm in Phoenix, AZ)?
Anything else I should check for to confirm/refute that the problem is the head gasket?
Anything else I need to know?

I can do most of the work on this car (and have for years and years) but I think the head gasket is a bit farther than I'd like to go. I'd appreciate any advice about this. Thanks-