This discussion of the wheelchair/handicap access just brought to the front of my mind one of the patents that Disney filed for over the summer, and got me thinking that this queue reconfiguration might be the precursor to implementing it....
A few months ago, Disney filed a patent for a system to allow for "off-line" loading of Omnimover vehicles (similar to how the special vehicle on Midway Mania pulls off to the side for handicap loading). It would allow the ride mechanism to remove a special car from the chain of vehicles (leaving a "carrier" of some sort as part of the chain) while the ride was still moving (or possibly put in "creep" mode during the transfer)
This car would then park to the side, where a handicap Guest could take as long as they needed to load into the car. It would then be added back into the chain of vehicles at the appropriate time. All of this with little-to-no impact in the experience of the other Guests.
In discussion here on the forums about the patent, it was presumed that this transfer system would be integrated into the stretch of ride track in between Unload and Load.
If this new queue setup allows wheelchairs to get all the way through the queue and through the preshow rooms, they could then go off to the bypass corridor just before Load and get to this new transfer point. And because this stretch of track isn't seen by 99% of the Guests, they could do a large chunk of the construction 3rd shift, possibly only closing the Mansion for a short time for final installation of the vehicles.
-Rob