IDEA After you buy a single ticket only and you have done the DL thing or maybe this is the part of day your feeling like you want to go see it, you can always go back out and UPGRADE to the park hopper for DCA the same day at the ticket booth.
They do not have a problem with that. Plus you might see in DL the dream team people standing around in a certain area handing out fastpass necklaces run over there, ask people where they got theirs if they have them and if it just happened run like heck to that area and get them too, if you have alot of your people running and you miss it, they will give you one in City Hall since most of your people got them, and if that happens for you, then you have an automatic tic for DCA because that will get you into that park, or visa versa also. We have asked people alot and ran as quick as we could to that area and got them too, works every time.
If you do not see them by at least 10:30am at DL they they won't be out anymore. Now DCA we have won them over there at the latest at 11:20am because they open up later. I think it is easier to win them there and to run its more spread out over there to get through people to run.
Now once again they have told me this as we win them, that if we do not have a park hopper to go into the opposite park we can now get in with the fastpass necklace. We never had to use them for that because we have passes.
So go in with a single ticket check everything out and you now want to see DCA then go back to the ticket both and upgrade.. Imagine some people getting there only buying the one park ticket then thinking darn I should of bought both after all, thinking they had to do it at the begining.
Not at all, you can even verify ( verify a couple times at least because no one answers down there the same way) , even if you bought your tickets somewhere else, just bring your receipt to be safe.
I love DCA also, my kids are little 11,9,6 and there are days we are there all day. My kids ride all the rides not afraid of any of them, my 6 year old can't wait to ride screamin, still to short.
You'll have fun!!