Forum breadcrumb class - where to start?

[eluser]TheFuzzy0ne[/eluser]
OK, I'm still at a loss here. I can easily get the breadcrumb for the current forum, but I can't visualise how to do the same thing but from a forum thread (if that makes sense). I'm not sure if I should be doing this all with a single call to the model, or if I'm expecting too much as usual, and it should be done with two calls the the model - one for getting the forum breadcrumb, and one for getting the thread title.

I can't believe something so trivial is stressing me out so much...