Just adding to the above, be sure you get to the GCH CAP entrance about 30 minutes before the park opens, otherwise you will face a lengthy wait to get in.
There is only 2/3 people doing a bag check and there are only 2 turnstiles to enter. Also, if you are using a multipass for the first time you have to have a photo taken and each time you enter either park they have to scan your ticket for the photo.
That doesn't sound timely but trust me, having been there in January, the delays at the GCH entrance will cost you if you want to get in at the start of EMH. We got there 15 minutes before the park opened and didn't get in until 10 minutes after it opened.
Also, another alternative is to go to TSM and CS, as these have no waits and you can ride multiple times. You can always go back for a RSR fastpass before it opens to the public as they aren't allowed to join the line until then.