If you're not a large group and you can be flexible on your day you go ( coming from the UK it's likely you'll be giving them quite a few days) I think you have a good chance of getting a vacancy at DC, failing that there are a number of snorkling tours offered in the Crystalriver area, because they go out early it mightmean you have to book into a nearby motelto makethe 8.00 start as it's a couple ofhours drive from WDW.