It's going to be very crowded that week, so even though some people recommended getting a hotel that has a kitchenette, you most likely won't do any cooking, you'll be eating in the park a lot because you'll lose a lot of time standing in lines, and wont' want to leave to go get meals.
The rooms at the Disney hotels do have a small fridge, so if you want to save some money, buy some milk and cereal from a nearby grocery store and eat breakfast in your room. Bring fruit and snacks too.
The strollers at the park are nice and big, definitely big enough for a 5 year old, I'd recommend them. You might even want to get a Disney credit card. We don't have one, but I know that they used to give you free stroller rentals if you had a Disney credit card.
We have annual passes, so when we have stayed at Disneyland, we haven't booked a package with tickets. We always stay at the Paradise Pier Hotel at Disney. It's beach themed and the pool is nice, plus fun waterslide. This is the least expensive of the Disney hotels. The Disneyland Hotel (original one) is about the same price right now, but that's because they are doing major construction there (we were just at Disneyland two weeks ago). I'd be wary of booking a room there, it might be really loud. The construction is supposed to go on for quite some time.
BTW, they say check in is at 3 PM, but you can get there at 1 PM, and your room is usually ready. Or get there even earlier, and they will hold your bags until your room is ready, and you can go in the park.
Also, the pool is freezing at the Disneyland Hotel, the Paradise Pier pool is much warmer.
The Disney CA Grand Hotel is really nice and the closest to the parks, but very pricey. Have a great time! :)