The classes should be really helpful! This stage is really scary and daunting. DH lost about 15 pounds nearly overnight b/c food suddenly frightened him so much he just couldn't deal with eating.
Things we've figured out (and your mileage may/will vary b/c they have different bodies):
If you're going to eat a sugary treat, make sure it's proper sugar, not something based on corn syrup (like Dole Whips). DH has the monitor and can SEE the differences in his levels between cane sugar and HFCS or corn syrup solids. His readings go much higher with the corn syrup based things.
If you're going to eat a sugary treat, try something with cinnamon in it. We actually found out about the cinnamon thing when I made pumpkin muffins from the
Disneyland AP website. There was cinnamon all throughout the recipe, and he felt SO guilty eating a muffin, but the next morning he hit an alltime low since he started monitoring. Every time he has cinnamon it's like that; he actually had been given a cinnamon supplement a few years before his diagnosis, and started taking them again, and it is a drastically GOOD difference.
Figure out what works for HER. DH is very opposed to using artificial sweeteners, and has had to figure out just how much cane sugar he can have. Others are fine using artificial sweeteners. DH used the stevia/truvia stuff (it's based on an herb) but ultimately wasn't a huge fan, and it's $$$.
Get kitchen tools that easily measure portions. She doesn't want to be eyeballing things like pasta, b/c that will probably lead to too big portions. DH is so happy we already had the kitchen scale from doing WW a few years back.
DH found the side effects of metformin to be too difficult to deal with, so he has had to manage this with ONLY diet and exercise...his endo keeps wanting him to try the drugs, but has accepted that DH can do really well without it, and any benefit from the drugs would just be gilding the lily.
Exercise has amazing benefits on the blood sugar levels.
Eat regularly.
At WDW, follow all of the above (especially making sure she is eating and drinking water very regularly). Since there isn't much time between now and then, she might still be in the timid stage, and that's fine. It'll probably change the trip, but it will probably be for the better. She might have not been feeling all that well before, and these changes in diet will probably help her feel better; that was DH's experience. He feels SO good now, though it took awhile for his head to dump the "but I want to eat whatever I want" thing.
Thanks to his endocrinologist, we found out something else that had been going on in his body, which other MDs and NDs had been refusing to test for. For 3 years. 3 years he's dealt with these symptoms and they all refused to just add the extra bloodwork to what they were already doing. So a good endo, one who will deal with you as an individual and try to trust you (it took some work to get DH's endo to trust him and believe in him, but he's there now), can really really help, and I hope you guys seek one out!
The family doctor that saw DH after the urgent care guy diagnosed him REFUSED to refer to an endo, and gave him horrible information. WE had to seek everything out, we called MultiCare, got him in the classes, we had to find a good endo (and get the urgent care doc to refer him, bypassing the family doc), etc etc etc. Even for type 2, they are incredibly helpful.