Hi K.,
Ias with my daughter and her husband when they took their 6 month old daughter to Disneyland. She had a ball, taking pictures with the characters, riding the rides and watching the parades.
We took her on all the rides in Fantasyland. If the rides are jerky, you just have to hold on the child a little tighter so the body is not jerking around. You can also take the baby on its a Small World, Pirates of the Carribbean, Monorail. You can go to Toon Town. We took the baby on Roger Rabbits ride but with this ride you can not put the baby on your lap, the baby has to sit down in the seat but you can hold the baby tight because that ride is jerky.
Strollers: you can rent the strollers there but you have to remember you can not take them to downtown Disney, so I suggest you bring your own stroller (double stroller so you don't have to carry the 5 year when she gets tired) and then you can take that anywhere. Bring plenty of snacks for both children because they are expensive once you get into the park. Don't forget the blanket.
If there is an adult going with you who don't like riding all the scary rides, you can have them watch the baby while you and your husband enjoy the rides with the 5 year old. That is why my daughter and her husband bring me along. I love going to Disneyland, but my stomach can no longer handle them fast rides so I watch my granddaughter who is now 3 1/2 when they go on them roller coaster rides but now she loves the Matterhorn.
You can always go to City Hall and ask them what rides you can take the baby on. Also while you are at City Hall, make sure you pick up a Birthday Button for your daughter and a First Time Disneyland button for everyones first time. With the birthday button the Disney Cast Members will wish her a Happy Birthday all the time when they see the button. I also heard you can get a free ice cream at one of the carts, but you can also ask that question at City Hall.
Have fun and enjoy.