There are no queen posts or other intermediate rafter supports in the barn frame.
The frame is a constructed from hewn white pine(pre-1900 and definitely good quality pine), the principal framing is all around 11" square.
But it is a simple frame, even the 26' crossbeams have no intermediate posts.
The existing rafters are not suitable for the conversion(gambrel roof with plywood gussets).
I felt it would be cheaper to use conventional roof trusses than to build a timberframe roof system, including an intermediate support(queens, purlins, etc.)
However, conventional trusses would require the 2nd storey wall hieght to be around 8', as they will have level bottom chords.....although a few "raised chord" conventional trusses are being considered for the center section above the stairwell.

Maybe I'm wrong to assume that 15-20 conventional trusses would be cheaper than 15-20 rafter sets plus 8 queen posts plus 80 feet of purlin plate plus around 20 braces?