You can check your bags in at any time, up to about 1pm. That's when the RAC counter closes for the day. I like to take my to be checked bags with me in the morning and check them on the way to a park, or breakfast. Usually this is about 6:30-7am. Then, I leave my carryon bags with Bell Services. You need to be back at your resort no less than 45 mins prior to your DME pick up time. You should be out at the bus stop, ready to go, 15 mins prior to that time. And you'll need time to get your carry on bags out of storage, and someone always needs to make that last minute run through the gift shops, and the bathrooms!!!! So, aim to be back at the resort an hour prior to your p/u time. With a 7pm flight time, your p/u time should be around 4..give or take 15 mins either way. So, with that in mind, plan to be back by 3, which means leaving the park no later than 2:15.