Hi Adam! I love your question! You are truly Prince Charming!
To begin - your wife and her doctor know best. If your wife's doctor feels you need to cancel or postpone, please listen to the medical provider.
That being said, I visited Walt Disney World Resort when I was 6 months pregnant. There were times I was tired and a bit worn out but it was an amazing vacation! My son loves that his first time at Walt Disney World Resort was while he was in my tummy. He calls it his "bonus trip."
I didn't use a scooter. If your wife needs one, you can rent one when you arrive. It's so nice that you are thinking about things like this.
Because Walt Disney World Resort is her "favorite place on earth," I'm guessing she has visited often. When you are making plans, I would back off from what you typically do a bit. Before kiddos, my husband and I would go full force all day. That didn't work when I was pregnant. We took a lot of breaks and spent a great deal of time in the attractions that are inside and air conditioned. We also went back to our Resort hotel for an extended break and pool time. The pool was relaxing and great for my muscles.
If you typically dine at table service restaurants where
advance reservations are encouraged, you might want to see how she is feeling when you are outside of the cancellation window if you make several reservations. With my daughter, I could barely eat anything. With my son, I wanted to eat everything in sight, so be flexible with your plans. Also, make sure she stays hydrated!
When I was pregnant, I slowed down and was awed by things I had never noticed before. Being at Walt Disney World Resort when I was pregnant was a truly magical experience. I know it will be the same for the two of you. Enjoy every magical moment and take lots of pictures! After all, it's your baby's "first visit!"