Jennifer,
Definitely go with the single stroller that reclines. I find one of the biggest uses of a stroller is as a site for a quick cat nap.
Here are some other stroller suggestions;
Make sure your stroller is colorfully marked. Not that people steal strollers, but absent-minded parents often find themselves hours later pushing someone else's stroller. Honest mistakes, but a real pain. Let the kids help create signs and other fun stuff as a pre-vacation project!
Pace the 8-year old. Make sure that you are giving him/her plenty of time to rest, especially if you are covering a lot of ground.
Use the Baby Care Centers as a cool-down zone for all the kids!
Take note as you go through parks for good locations that provide shade and a bit less noise. These are where you might return for an in-stroller nap break. Here are a few suggested locations;
- Magic Kingdom: Rose Gardens to the left of Cinderella Castle (towards Tomorrowland)
- Epcot: Rear of the Italy or UK pavilions
- Hollywood Studios: Sunset Ranch, towards the Rock 'n' Roller Coaster
- Animal Kingdom: Dining grottos by the Flame Tree BBQ
Have a magical vacation!