Disneyland Space Mountain Queue with ECV

One of my group on an upcoming trip will have an ECV. She wants to see the queue for Space Mountain but is probably not going to ride it due to motion sickness issues. How much of the queue will she be able to see if she uses whatever they do for ECVs? Will there be any problem with the rest of our group getting on the ride if she decides to bail once she's at the point where she has to make that decision? Four of us total.