What fun to be planning your first trip to WDW and especially to be sharing it with your daughters!
Yes, you are more than welcome to bring a back pack; in fact, you'll see people carrying bags of all shapes and sizes. Just to let you know, all bags are searched prior to entry to the parks.
Now the question of what to do and where to eat is a pretty big question to answer. I'd encourage you to begin exploring the WDW website with your daughters.
This is a good place to begin because you can visit each of the parks and see what attractions each one has. It may be helpful to have you and your daughters each note a couple of must-sees rather than making it a goal to see everything, which is nearly impossible to do. And here is a great surprise - you can make a customized map of each of the parks highlighting your must-sees, and Disney will send you a copy of it for FREE! Click
here to make a map.
With so many dining options between the parks and resorts not to mention Downtown Disney, this can also be overwhelming. Click
here to begin searching the different choices and begin to think about some simple choices: do you want to have some table service meals (these will need reservations)? do you want to dine with characters? do you want to try a new cuisine? Then, you want to start to think about your daily itinerary to match up dining choices to what days you'll be at certain parks.
These are just some ideas to help you get started (we are limited on space); please don't hesitate to send more questions our way. We are all eager to help Disney guests!