We are also going with a 2 and a 6 year old in November. Based on our previous trips and past experience, this is what we are doing -- since we are driving, we ARE bringing two single strollers (a cheap umbrella stroller and the really old banged up Aprica from when the 6 year old was a baby). HOWEVER, having said that, if we were FLYING, I would only bring one and then POSSIBLY rent one at a park for the older child on a day we plan to be in the parks a really long time.
Here's how it works for us:
MK: the long walk is the walk down Main Street -- upon entering, she is way too excited to sit in a stroller. We'd just park it all morning in Fantasyland and Toontown, so the only times we'd use it are getting to the left side of the park and leaving, so we probably won't even bring our second one that day. Plus, if she's really pooped, the 2 year old won't stay in the stroller the entire time anyway.
Epcot: here, we will probably bring our second stroller. It's just SUCH a long walk from one point to another that it tires them out needlessly.
MGM: debatable. There are enough sit-down shows that she shouldn't get TOO tired, but the constant criss-crossing of the park we do to get from one show/ride to another can wear them out. We probably won't bring the stroller the first morning there (only staying until lunch) and decide what to do after that point.
AK: Also a tough one. There's a lot of walking, but we have found the paths aren't really conducive to umbrella strollers -- they're a bit rough and rather narrow. Again, we tend to split our days up into small segments (we spend a morning somewhere, leave at lunchtime, come back mid-afternoon) so we don't try to do an entire park at once, and given that, we probably won't bring a stroller here.
Keep in mind that, depending on where you're staying, you may want the stroller just to get to the bus stop. I've stayed at the former Dixie Landings twice and, even though we weren't THAT far away, it was nice to have the stroller for the older one on the way to and from the bus or food court. Kept the whining to a minimum. Same applies to most of the other moderates. We actually didn't need one for her at All Star Movies when she was 5, but were in a close building.
Hope that was helpful and not too long! Feel free to e-mail me if you have any other questions!