Rod,
Your enthusiasm and what you have done with your mill are great. But I think what Kieth and likely others (myself included) are saying is that all that work into that stair case. All the fuel, all the time, all the blades, the re-sharpening, the time to cut the trees, skid the logs, chainsaw gas, files, all of it, is going to rot in the ground in just a couple of years. Beyond that, it will start to suffer and look bad (not that pressure treated looks good) in VERY short order.
There is a simple reason why we as a society no longer build things this way any longer. Its because when it WAS done this way there was no better option. It was the ONLY way. This isnt the case any longer. There are other ways that are simply better and in all honesty if you account for all of your expenses they are cheaper.
I think the work your doing and your passion with regards to the mill is great. But its similar to your picnic tables and other items that are simply not dry (there is no way they can be) when you build them. It will simply be a matter of weeks before the fasteners begin to loosen up because the boards they are holding are getting thinner and thinner. Virtually ANY finish you put on such a project (especially any type of film finish) is likely failing within hours of you putting it on.
There is a reason why things are done the way they are today, air and kiln drying, preservative treatments or very specific choices of species for a given project, paying attention to wood movement and cross grain situations, and so on, and its not because people just enjoy overcomplicating things or wasting time and money, its because its whats needed and whats right.
Again, I think your passion about this is phenomenal, and you commitment to working hard is obviously on par with your passion, but the sad fact is most stuff will simply self destruct in very little time. Of course if your customers are aware of this then more power too you.. just keep cashing the checks.