I've been to Magic Kingdom on my actual due date (and at various times during my third and fourth pregnancies, sometimes for 8+ hours at a time, often for much less), so WDW is definitely do-able for pregnant women without a stool or the like if your wife is healthy. If she has a disability that would make standing for a long time difficult, definitely consider checking about the DISabilities board. Pregnancy itself isn't a disability, but it may cause conditions that legitimately qualify as one. I had pretty bad sciatica with #3, so proper footwear, walking slowly, and sitting whenever I could were important. And drink tons and tons of water. More than she could ever think she'd need. In Florida, pregnant women sweat for two!