I have a similar situation.....I'm going in August and am going to be there for a full six days (eight counting our traveling days) But I am told if you are there for that long, a DAY OFF is recommended, or it because unbearably exhausting. So I have a day where I am just going to relax at the pool and do a spa service or something. Therefore, my "park" days are cut to 5. I am going to US/IOA also....I have alloted a full day for each, though in the past I have done both in one day, but this was with my parents who did not go on the "big" rides. After this I only have 3 days to do 4 disney parks. I do not want to skip one because I have not been to Disney since 2000 and before that 1996.....and both times I couldn't fit everything in, So I decided to do AK/MGM in one day.
I'm sure some do not suggest that because a full day at one park will feel like you're not rushing but I don't have the time nor the money to do anything but do these parks in one day. I decided to go to AK on the day it has Early morning Hour......then hopefully it will not take me that long to do what I want in the park. Hopefully I can get out and grab some lunch before heading off to MGM and spend the rest of the night there. I hope this plan works out for me...but I'm sure you can figure out something to do as well