First, there are no half day, full day, or two day parks. The time it takes to see each depends greatly on what you are interested in doing, how long you stay, and how long you consider half a day (3-4 hrs: morning to lunch or 6-8 hrs when the park is open 12 hours or more, but you only stay half the time it is open). People who say AK and HS are half day parks and then list out what they do usually only include about 3 to 5 attractions at most at each of those parks. However, if you did 75% to 100% of the attractions, it would take at least a full day opening to close to complete everything once. Those two parks are never half day parks for us because we like to do more than just the 2 or 3 headliners. We always plan a full day at each park and still run out of time. For instance, I have been trying for years to catch the Flights of Wonder show at AK, but have never been able to fit it in.
As far as which to try, I think that depends on a few things.
Do your children like animals or dinosaurs? Especially, the toddler?
If your kids are big into either, they will love AK and want to stay all day. If animals aren't their thing, they may get bored quickly and want to leave.
For animals and dino lovers, youve got the zoo aspect as well as the safari. Youve got the petting zoo, the kiddy dino rides, the dino carnival games, and the dino play area. There are also the Wilderness Explorers Badges which are hands on activities that take 3-5 hours to complete alone if you do them all. Then there is the Nemo show and the Lion King show which both appeal to kids.
Other attractions that might interest your kids are the train ride and the Rainforest Cafe or the Tusker house character meal. The second is a very well themed buffet and a lot of fun with a Mickey and friends led parade.
There are other shows and rides at this park as well, but those are the ones I think would most appeal to your kids ages.
The second thing to consider is: Will the 2 year old sit through shows?
Both AK and HS have a number of shows, some of them very good, even for younger kids, but if your child doesnt have the attention span to sit through them yet, it wont matter how good they are. Shows comprise about half of HS attractions and rides themed more toward teens/adults make up close to the other half. So if the toddler is too young for most of the rides and cant sit through the shows, that doesnt leave a lot to do at HS. The main attractions for your whole family I think would be Toy Story, Star Wars, and Disney Jr. which doesn't leave a lot to do unless you are willing to split up or use baby-swap for the rides.
That doesnt necessarily mean you dont want to do HS though. If you think it will be the park you end up needing the least amount of time in, then it makes sense to do it as a half day park since it is open later. This way you could get the few things you really want to do here taken care of without wasting a full day later on. However, if you are asking about whether to do HS or AK altogether, then Id say that unless your kids hate animals, AK is the better choice for entertaining a toddler.
