We took our 18 month old DD and she had a blast! I was a little concerned about her feeling confined to the stroller for long periods of time, but it didn't end up that way. She went on every ride she could - Buzz Lightyear and the Haunted Mansion were her absolute favorites, believe it or not...then again my DD5 loves the Haunted Mansion (she thinks it's silly), so I think anything Big Sissy loves, Little Sissy decides to love too. The rides that you decide to go on should depend on how well put your toddler will be. My 18 month old was good about staying seated and buckled (much to our surprise...she never sits still for anything else!), but we still went on all the rides with her (yup...Mom went on Dumbo). Some of the rides, she can sit in your lap, while others really require her to sit next to you. Assuming your daughter enjoys the rides, like both my DD's always have...there isn't much she CAN'T go on, except the big rides, as another poster said.
Oh, and my DD is NOT a good stroller napper, normally, but for some reason, at Disney, she'd conk out cold everyday without fail (three hours, one day) at 1pm. One day we brought her back to the room to nap, and she wouldn't nap - as soon as we gave up and went back to the parks, she fell asleep in her stroller (go figure!)...I guess the stroller was more familiar to her than the resort pack 'n play. Either which way you do it...be sure to let your DD get a good nap! Most important for your vacation enjoyment!