3 days getting up early is hard! Have you had a time change working for you so far? If so, that advantage is running out. If not, well, it's hard to wake up early like that.
If I were you, I'd just happily and kindly go on into the parks. If they want to leave before you do, let them! If they feel that vacations are for family to be together, well....ultimately, it's more fun if everyone gets to have fun. If you're not having fun with their choices, where's the fun in that?
It took quite awhile to convince my little family that when I said "I'm going to go to the parks now, you guys sleep in" I really meant it, and wasn't being snarky or passive aggressive. Because when I was ready, it was good timing...waiting for them made me later than I wanted to be...so then I wasn't getting what I wanted, and they weren't getting what THEY wanted, and we just trudged in not having as much fun as we should have been having.
Hubby gets up so early for work, he wants to sleep in. DS wakes early if hubby is home, he either sleeps in or plays in the bedroom waiting for me to stop dozing if it's just me. At Disney, he wants to sleep in. I am normally a very sleepy person, but at Disney, many I'm just UP. and it is so much better now that they truly understand that if they want to sleep in, it's OK with me, as long as they don't mind me slipping out the door to hit the turnstiles before they open.
So even if you waited for them...if they want to go back to the hotel early, let them. This is your vacation too, and you deserve to have the fun you want (assuming of course the kids can be taken care of, etc etc, don't just leave 'em, LOL).