I've never been to DL, but just being a generally cautious person anyway, I'm a bit concerned about leaving the stroller and any contents.
I don't know if I'll go to the trouble of locking up my stroller, that does sound like a huge hassle! But others have posted how they've made their stroller (even a rented one) more easily identifiable, such as decorating it with ribbons or balloons (or even crumpling a diaper into a clear plastic bag and hanging it from the handle, LOL!)
As for the stroller contents, I would never leave anything in there that we would hate to lose, whether it's expensive to replace or not. One post said a child had a very full autograph book by the end of their stay, and it got stolen from their stroller, so sad!
I bought a backpack to carry our things in; while we're on the move the backpack will be in the stroller basket, but when we have to leave the stroller, the backpack will be easy to carry along. (I read somewhere that bags are sometimes frowned upon for taking on rides, but backpacks are not a problem.) I'd probably leave water bottles, snacks and the like to lighten the carrying load.
We'll be buying souvenirs, but will either buy what will fit into the backpack, or shop just before leaving the park. Alternatively, if you are staying onsite, you can have your purchase sent to your hotel, though it will take a day to get it and might be more of a hassle than it's worth for some things. (Don't do this for a toy that your child will want to play with as soon as you get back to the hotel!)
That's my plan...
PS. Fidoprincess, not sure if I'd need your 2-bag system, as we'll be heading back to the hotel every mid-day for naps, but it's a great idea! Will just have to see how we do in the first couple days. Or maybe the first time I try to cram everything into a backpack...
