How tall are they? I brought my 4yo in Feb and he could do most everything in the parks, since he was 42" (40" restriction on quite a few rides). Hopefully he'll be 44" by December (right before his 5th birthday) and then he'll also be able to do Mission to Space and Space Mt. Still won't be able to do Rock N Roller Coaster and the spinny ride at AK (something else, too, I think), but he wants to do everything and I'm glad he's tall enough to do most everything.
T&B