Remember AK closes early and has no fireworks. If you do not have the park hoppers then your day would be over at 5 or 6. I would choose Epcot or MGM over AK. Also Epcot has test tract, mission space, soaring, and crunch for the little one as well as the world showcase, street performers, and make your own mask at each kidcot station. As you can see Epcot is one of my favorites!
But in your case I would seriously look at Universal package for $300 ( three ticket packages of 5 consecutive days with child free for $99) then add a one day pass to MK which would be approximately $360 (6 times $60 approximately) for a total of $660 and six full days of park fun! It would definately make your buck go further! It would be hard to be there for seven days and only 3 days at the parks. Check out the Universal threads for more information.