Hey Gweed, questions about some alignment choices:
Why Donlands instead of Pape?
The reason I chose Donlands is because of the easy yard access. With Donlands, the existing Greenwood yard can become the DRL yard, with a new Bloor-Danforth yard being built at Honeydale (along with a new integrated TTC, MiWay, and GO terminus). There isn't an obvious point along the DRL route for a yard (or an inexpensive piece of land), but there is enormous potential at Honeydale.
Also, there will need to be a significant reconfiguration of whatever Bloor-Danforth station is chosen as the interchange point with the DRL. By choosing Donlands, that's a much easier station to either partially or completely close in order to reconfigure the station. It has low ridership as it is, and the couple of bus routes that end there can easily be rerouted to Pape or Greenwood. Ditto for walk-ins.
Why Dufferin instead of Roncesvalles? (I consider Sunnyside to be an incredibly important transfer node)
Or an interchange station at Dufferin/Queen?
I chose Dufferin because it's an incredibly busy bus route. The southern portion of the route has no potential for anything on-street, and putting a streetcar there in mixed traffic to provide extra is highly unlikely. Roncesvalles may be busy, but at least it has a streetcar route.
It's also a few KM shorter of a route than going up Roncesvalles. Also, with Roncesvalles you run into a problem: there isn't really an alignment north of Bloor that doesn't duplicate the rail corridor (and thus duplicates the GO REX service). By going up Dufferin, you're able to run under Dufferin until Dupont, and then cut diagonally across through the hydro corridor, then through Earlscourt Park, then the hydro corridor until Rogers, then up Rogers to the rail corridor for the last stretch into Mount Dennis. This gets you a lot more coverage over midwestern Toronto.
Also, Dufferin is an ideal location for a western transit hub at Dufferin & Queen. A subway line, an LRT line, a streetcar line, and 4 GO REX routes. It would no doubt be a complicated engineering feat, but so is the dig-down at Union, or the 2nd platform at Union subway station.
Is there even room for an LRT ROW on Queen between Ronces and Dufferin?
It would be tunnelled from Roncesvalles to Dufferin under Queen, very similarly to what is being done on Eglinton now. In essence, all LRT traffic from the southwestern side of Toronto would be feeding into the new Parkdale transit hub. It also sets up as eastward extension of the LRT under Queen to replace the streetcar service (eventually). Again, with similar specs to what's being done on Eglinton.
All very good questions though, and certainly ones that should be asked.
The biggest mental battle I'm fighting right now is what to do with the Don Mills BRT. Ending it at Seneca is a logical terminus, by I also think it would do a lot of good if it could be extended into York Region. I'm just not sure what the best alignment to do that would be. Or would it be better to do another BRT along McCowan from Sheppard-McCowan connecting to Markham GO?