Welcome and glad to hear she is feeling well so far.
IMHO, a wheelchair or
ecv would help her as much or more than a GAC.
The distances between attractions are immense and walking that much makes people tired even if they don't have health challenges. If she has an ecv or wheelchair, she would be able to bring it into line with her, even without having a GAC, so she would not need to stand in line. You can rent an ecv or wheelchair from the parks (
ecvs are sometimes in short supply, but wheelchairs should not be a problem). A lot of people like to have a wheelchair at the resort too; If staying on site, you can ask to borrow a wheelchair from the resort. These are first come, first served, so there may not be one available or the one they have may be an extra wide when you need a regular size. You can also rent from one of the local Medical Equpment vendors. (My DD did something to her computer and erased the file that had my notes on - so I can't give you a handy link. The 2 places that disABILITIES Board posters say they rent from most are Care Medical and Walker Medical).
Here's a link to the DIS page on touring with a wheelchair or ecv.
GAC stands for Guest Asistance Card and it basically gives CMs some guidance about what accomidations you need. You don't need a doctor's letter, but she does need to be prepared to explain her needs. You request a GAC at Guest Assistance/Guest Relations in any of the parks. The card does say that it is not meant to shorten your waiting time (and it usually won't), but it might allow you to wait somewhere more appropriate to her needs, like out of the heat and/or sun (both of those might be important to her with her health needs). A GAC is usually issued for the length of our stay, is valid at any park and can be used by the person with a disability plus up to 5 members of their party. Some of the attractions are still a long ways from the entrance to boarding, so if she has a GAC, but not a wheelchair, she would still have some long distances to walk.
