I assume you are flying in. Your room will probably not be ready when you check in, but you can get your magic keys, have the hotel hold your luggage, and visit a park using FOTL.
Bring your reservation with you, and call the hotel before flying down to make sure your ressie is still on file. The HRH overbooks during busy times. So if you don't want to get bumped, you'll have to ask them about that.
Checking in early is the best idea. You could fly in the night before, stay at a cheap off site hotel, and then check in at 7am. Sometimes a room is ready early in the morning. Since you are visiting in July, the parks stay open until 10pm, so you'll have plenty of time to tour the day you arrive.
It's just that flying in the night before, and checking in to the cheap hotel, will make your visit feel longer, and could result in a better check in at 7am versus noon.