No it is feasibble as long as you work in rest/nap time. Even if our son naps in the stroller we go back to the resort for rest and downtime. This is what I would do.
Day 1 & 2 MK & EPCOT. Go first thing at opening (or son is an early riser so making a 8 or 9am opening is no big deal for us but depends on your child), ride a few things. You can probably get in 3 rides if you utilize FP's and a character meet. W have lunch early around 11:30-12 because that is when he eats at home. Then go back to hotel for nap or swim. Return to a park around 5ish for dinner, another ride and just enjoying evening activities. How late you will stay depends on your child. This trip my son will be 2 1/2 so we may stretch him until 9-10 because he has occaisonally stayed up that late at home though is regular bedtime is 8pm. We will do this one night as not to exhaust him. For us we prefer to do this at MK because Illuminations may be too much for him.
Then I would split AK & HS one day. In fact we are doing this next trip because we prefer to do MK more then one day. We will go to AK first thing in am, ride a few rides (for us this the safari, Rafiki planet watch, the new one in Pandora and letting him play in Dinoland. Our lo won't really sit through the shows. too much waiting in line then sitting but again it depends on the child), see Pandora, eat lunch and go back to resort around 1 pm. We will go to HS in evening at eat the character meal at H&V with a 6pm ressie. We will see Disney Junior and possibly ride TSM if it's not crazy. Otherwise there isn't too much at HS for toddlers so that was the planning thought. He did like the Star Wars fireworks in Oct. but they are not showing on the schedule yet.
As mentioned above, you can plan but prepare to make changes and be flexible depending on your LO. This will be our fourth trip with our toddler and it can be the most fun, but you have to let them rest, eat and stay a little on their schedule or they may have a break down lol! Hope this helps..
