Based on this:
the ball is passed around the post, wing and corner upto the time that an open shot presents itself.
It sounds like the pace would be slower than normal.
the triangle in BB will have more medium range shots
The focus would be midrange/inside then?
So, very close to a Princeton, like you said. According to the manual, Princeton is "outside/inside focus (fewer 2 point jump shots, regarded as outside by GDP), decreased pace." So, I would think that where Princeton is regarded as Outside focus, slow pace, Triangle would be inside focus, slow pace as far as the GDP. The actual gameplay would be a bit like Low Post, but with a better balance between midrange and inside shots. Three pointers would be as rare as they are currently in Low Post and Look Inside.
What defenses would counter the Triangle?