If you're set on going at all, I recommend going all the way and getting the hopper. We did this 2 weeks ago and found the crowd levels to be so heavy that we "hopped" just to try and avoid them. June 18 is a Wednesday, we were there on a Monday and DL was unbearable by early afternoon.
I suggest DL in the morning and
DCL afterwards but that will leave you having to do single-rider for RSR. (We missed out on the FP's and the single-rider line was 30 minutes long by 11:30). Maybe try ducking into DCA first thing just for FP's (I "think" RSR and Soarin' are disconnected) and then hurry back to DL for the rest of the morning.
If you are going to do just one park it should definitely be DCL, but that might not seem "
Disneyland'ish" enough for your DS. Good luck!