We went last year Nov with other family (4 kids total, ages 3,4, twin 2) and here are my tips;

-Epcot with little ones in my first trip with DD was a waste. Don't get me wrong, they had fun but there were no true attractions that is like whoa, i want to bring my kid there besides just seeing it in person.
-Park hopper IMO is a waste as their is so much do to in 1 park, its a process getting into a park and now you want to turn around and do it again?
-Yes, i agree with a AP and taking a day or two off as it is alot of work
-mousesavers.com is your friend
-undercovertourist.com and the app is really your friend
--this allowed me to pick and choose what park i went to on what day, they give information as to special park event and traffic.
-bunch of apps that have GPS and times of meet and greets
-We did 2 smaller meals in the park instead of 1 full meal. Food is expensive and you don't want to sit and eat while you can ride and have fun! We ate breakfast at the hotel (had kitchen, etc..) and dinner was outside on the way back or local restaurants.
-Downtime Disney is plenty to see and do for the kids (T Rex dinner and LegoLand is a must)
-Fastpass is your friend!!!
-If you plan on watching parades, i recommend getting a good spot up to 20-30 mins in advance as this is the only way the little ones will see it. Find a place and hunker down.
-The photopass is totally worth it ONLY if you take alot of pictures. We took a ton of pics and combined it with our other family and purchased the download. Makes it well worth it to see memories, etc.. Make any type of altercations to your pictures first, then purchase as you get templates etc... too.

It was our first time go, DD was very happy. It was a long day but we stretched everyday into an all day event. We got 5 days of tickets, went to each park once and Magic Kingdom twice (well worth it) as orginally, we were going to hit all the parks. Epcot, like i said, you could pass with kids. As an adult, it was awesome but keeping kids entertained may be a challenge. We got them ice cream and were happy to be outside after a long day of travel.
Anaimal plant is a must IMO. Hollywood studio i'm on the fence about. If you need a slow down day, this is a place to be. It was fun but easily passable. We went because DD enjoys most of the PIXAR movies (Toy Story, Monsters Inc, Cars, etc..) Fastpass Toy Story Mania!!! Not sure you be able to do it with 3 kids 2 adults as its a ride for 2 people in a car.
Magic Kingdom we knew was two days and we managed 10 hours in each park. It was truly magically.

Enjoy your time!!!