Help! We've rented a double side-by-side stroller in the past for DD & DS when we have gone to Disney in the past. The last time we went in May 2007 they were almost 6 and almost 4 and it was getting heavy for DH to push. We are going again in January 2008 - so the kids will be 6 1/2 and 4 1/2. What would you do? Here are the options we are facing:
1. Rent the double stroller so that the kids will last in the parks and hope that DH's back doesn't give out?

We don't own a double so renting is about $75 for the amount of time we will be there. But money is not really the issue here. Ease of jumping on the bus, tram, boat, etc... is what I'm thinking too. The kids like the stroller for obvious reasons.
2. Take just a compact stroller for the 4 1/2 year old? My worry is that the kids might fight over who's turn it is to sit in the stroller next. But at least I would have some rest on wheels if needed. Also would hold our backpack nicely.
3. Don't use a stroller at all. The thinking here is that they both might be "big enough" now to walk the parks without a stroller. But I'm not sure.
Anyone else have to make a decision on when to give up taking a stroller? What did you decide? How did it work out for you? I have time to think about it and see if the kids might be able to handle the long walks from buses to parks, etc... Thanks in advance for your advice!