Hi Mr. Churchwell
I think you're making a good decision if the T206 fits your needs.
You're an experienced pilot and my guess is that if you can get the GTSIO engines in a 421 to TBO you won't have any problems making the right decisions on how to operate the engine in a T206.
My recommendation is to fly it by the book except for a couple of things.
1) Lean aggressively on the ground--this will help keep your combustion chambers free of lead build up and will slow the build up of lead on the valve stems.
2) Apply power gradually and always take off at full power. A turbo charged engine is always operated with the mixture at full rich at takeoff--there's no need to lean the mixture when taking off at airports above sea level.
3) Change oil every three months or every 35 hours.
4) I believe that an oil additive called Camguard is worth every penny. Add it to every oil change and when ever you add a quart of oil.
5) I believe new T206s are equipped with an engine monitor. Learn all you can about how to use it. Learn how to set in the warning trigger levels for cylinder head temperature. Do all you can to keep CHTs below 400 deg F.
6) Learn how to download the data from your engine monitor. If you want help deciphering it, sign up for
www.savvyanalysis.com. It's amazing how much these guys can tell about how you're operating your engine from the monitor data.
7) Type "T206H POH' in your favorite search engine window; you'll be able to download (for free) a pilots operating handbook for that airplane. Study it and learn the systems.

The POH contains performance data for flights up to 24,000 feet. The books seems to suggest that 75 percent power is the recommended maximum power setting at all altitudes. I agree. 65 to 75 percent power settings provide a good combination of performance, stable fuel burn and engine longevity.
9) If you're going to flying into the back country, get some specialized instruction for that kind of flying.
10) I have a copy of Sparky Imeson's "Mountain Flying Bible and Flight Operations Handbook" that I look at often. I suggest that this book will help you answer a lot of the questions you have about a wide range of flying topics.
The best thing you can do to keep your engine healthy is to fly often. Pretty good advice, huh??
Best,
Steve