We have a 6 year old and a 3 year old. We have a double jeep umbrella and we love it! You can only have a max of 50 pounds on each side and my 6 year old just fits. It is just nice to have for her to jump in and out of when she wants. Sometimes we will also just park somewhere and walk around for a while and come back for it later.
Only you know how your daughter will do..for us, we like to have the stroller. Some people may judge you for even considering it. My daughter will be close to 7 when we go in December and won't fit in the stroller we have..she'll just have to deal and probably get piggy back rides from her daddy when she gets too tired