This may have changed, but when I was on my program you could go pick up your Maingate in person somewhere in Celebration. If you're concerned have her ask someone when she gets there.
Also, bear in mind that her "free tickets" aren't endless. She'll get 6 days (again, unless this has changed but I doubt it has increased) and be able to let three people in per day. So if she was going to have friends visit her/you guys are coming to visit a second time, this could pose a problem. She also has to be present when you enter the park, so you guys will need to plan getting into the park around her schedule. She may be working very late shifts, so she might be completely drained at 9 am when you guys want to enter the park. If she's working in the park you want to go to, she really can't come let you in when she's on a break because of costume cross overs.
As a side note, as a daughter who did the CP and coming from a Disney family like you guys. I would have been unhappy if my family was visiting and I was working all day. Especially if they were using my free entrances. Even more so if they were making dining reservations that weren't around my schedule. It would be really unpleasant to know that my family was using my tickets and eating around the world while I was stuck at work. If I can make a recommendation, make a ressie for every meal. Breakfast, lunch and dinner. She'll get her work schedule before you arrive. Whatever meal she is free for, bring her to. She'll appreciate the free food (rather than cooking for herself) and the extra time with family.
Is she staying with you at the resort? If not, she'll have to use the CP buses to go everywhere to let you in. That is an absolute nightmare for any CP because those buses are not super and getting to where ever she needs to work would be over an hour detour. This may seem inconvenient, but try and enter whatever park is easiest for her everyday. Then just hop over to your actual park for the day.
I know this is a looooooooong rant. Just remember that if you're using her tickets, the only ones she'll get on her entire program, you should plan your schedule around her. I'm sure you will though!!
