Thanks for the extremely fast replies. We do plan on bringing an
ECV with us (my dad already has rented one for the time frame of our June trip in case she needs it). Will the GAC allow her to enter in handicapped entrances or will they allow it because she is an ECV? It will only be she and my dad using it. My sister, myself and 6 kids will use "regular" line entrances.
Thanks
Most of the lines actually are wheelchair accessible and you would all be able to wait together. These are called "Mainstream Lines".
In some attractions, you will all be able to wait together and board together because people using wheelchairs and
ECVs use the same entrance as everyone else.
Some attractions have things like stairways, or the boarding area is on one side of a track and the exit is on the other. Since those things are 'roadblocks' for wheelchairs and ECVs, there will be a bypass that allows those using wheelchairs/ECVs to avoid those 'roadblocks".
For those, you would usually wait together until very close to the regular boarding area or the roadblock. At that point, you, your sister and the kids would take the 'regular' path and your mom and dad would take the bypass. They do not need a GAC to use the accessible lines/bypasses. Having a wheelchair or ECV tells that CMs they need to use those.
There are a few attractions, mostly in MK, where the regular line or entrance was not able to be made accessible at all. Those attractions have a separate wheelchair entrance (most of those are in Fantasyland). People using wheelchairs and ECVs don't need a GAC to use those entrances. For those entrances, they will usually only allow 5 people plus the person using a wheelchair or ECV.
For shows, much of the time you will be able to wait together, but there are wheelchair spots in the back row with a seat for one person to sit next to the wheelchair. The rest of the party can sit in the seats just ahead of the wheelchair row or can sit anywhere else they want to in the theater.
The only reason she would need a GAC would be if she plans to walk in some lines and wants to make sure she can use the bypass to avoid stairs and things like that.
This will make much more sense when you actually get there and see how things are set up. If there are things that are still confusing after this explanation, please ask more questions.