I'm trying to figure out the same thing for our family's trip in September, so I'll be curious to see the responses you get.
Currently, I'm considering doing a Tue/Wed/Thurs one week, then spend Fri/Sat/Sun/Mon doing other stuff (but we have family/friends we can go visit in Ventura - our hometown - during those 4 days, so it's really easy for us to kill that much time), and then the Tue/Wed/Thurs of the following week as well.
We usually go to the parks for 5 days at a time, and we almost always feel like we could go again for another 5 days straight, lol. So it's not a matter of not wanting to get burnt out for us...it's just a matter of wanting to only visit on the least busy days of the week, while still getting to go for 6 days.