We would rebuild 4 bents (walls) that would give you 3-12' plus bays. This barn has high side walls so you can have a second floor loft with plenty of room for windows and standing room on the second floor.
It also has very big hand hewn pine timbers and a rare and exceptionally good set of rafters @ 2' centers. The barn is in excellent condition.
The barn footprint would be approx. 28’x37’ +/- = 1036 sq. floor space. If we did a loft in roughly 1/3 to 1/2 of the first floor you would get another 13’x28’ = 364sq.to 518 ft. of floor space.
A set of architectural plans for the Lynden Barn is available and included in the cost of the frame. Perhaps it would work, at least in part for your own building needs.