Ranking of parks, from best to worst, in my opinion:
1. MK - lots of stuff indoors, attractions very close together
2. Epcot Future World - You'll miss out on Test Track, but pretty much everything is inside, with multiple attractions in many pavilions
3. MGM
4. Epcot WS - pretty dismal in the rain...quite a bit of the entertainment is cancelled; it's not as fun to stop at the snack and drink carts in the rain
5. Animal Kingdom - simply miserable. I think that only the Lion King Show, Dinosaur and It's Tough to Be a Bug are inside. Everything else is outside.
I speak from experience. Of the 10 park days we had in late May/early June, it rained A LOT on 6 of them, and on two of those days, it rained ALL DAY.
Have each member of your party think hard about what they would want to be wearing IF they had to walk around all day in a hard or steady rain. Those little $1 disposable ponchos don't do the trick. I had a heavy -duty poncho from
Walmart. It kept me dry but I hate having to keep a hood on my head, plus when you take off your poncho, it can go inside out, so next time you put it on, you may put the wet side inside, etc. I would have preferred a very light rain jacket and a ball cap.
Take at least 2 pairs of shoes. On the first rainy night we got caught in a total down pour that left our sneakers soaked, even after we tried to blow dry them.
If your tickets get soggy, just go to Guest Services and they'll print new ones.
If you wear a poncho, take it off for character pictures.
Don't get discouraged. We had a great time, despite the rain. We even got to be on the first Dumbo ride of the day, without even rushing (of course, our feet were in about 4 inches of water.) The rainy morning at MK was great. We ran around and rode then things we ususally skip, like Dumbo, the carousel, etc. because everything was walk-on.
