I will go into more detail this evening when I get home. We visited the park last night and I snapped the pictures I required. I was able to develop four locations where an elevator can be installed with minimal visual and traffic impact, in all 4 cases it would be possible to put in a medium to high capacity elevator.
Because it is only a bi-level it would utilize a hydraulic lift system which would eliminate the need for a counterweight system thereby further compacting the design. A larger scale design of this can be seen in the Westfield Mainplace Mall a few miles from the park off the 5.
In order to increase traffic flow, and relieve congestion it would need to face outwards towards the castle on the lower level, and face inwards towards the train on the upper level. As I said there are currently 4 locations where this could be done with minimal impact. This will be hard to explain without the snapshots so I apologize but I will post those later.
Option 1, remove the planter portion that extends from either side of the platform entrance staircase and built the elevator right next to the stairs, literally embedded in the wall. I checked, it can be made the same width as the staircase platforms, and because of the size of the planter you are not taking up extra real-estate. If need be you can remove a small portion of the staircase platform to add more room. This will work, and it will not impede the exit staircase which empties out right next to it (because it is essentially where the planter is now).
Option 2, would require removing a portion of the platform that is currently recessed to allow the stroller parking and exit staircase. I would not recommend this method because it would require excavation, and it would essentially dump into the same exit as the standard exit does. Again the elevator would be recessed and would not add additional real estate to the bottom of the platform. It would remove real estate from the top of the platform but this area is currently not utilized to a great degree.
I still feel a Baggage type area building would be the best theme for the upper platform. I also checked to see what "view" would be lost... and found that you would loose the view of the tree which is already blocking the train behind it... IMHO not a big loss. For efficiency reasons I would recommend placing it at the rear exit, which would allow quick boarding of both elevator and train.
The primary drawback would be cost... aside from that it could easily be done and be fairly efficient. Again I apologize for the lack of photos, I will edit and post those when I am home this evening. I thought I had them on my laptop but I do not.