We really don't have a concrete sense of the quantity of notes RJ left for the prequels or the outriggers and never will unless they're released. It seems reasonable to assume that he sketched out the end of the main sequence in painstaking detail during his last days (and possibly the prequels as well in prior years), but at least on the basis of his comments about them, the outriggers seemed like a vague idea far from fully realized in his mind. I'm sure he left at least some notes from which they could be cobbled together, but I worry that it would be easy for us to imagine that RJ left more details on them than he actually did.