I will chime in on this, with a caveat. Only you can know how you will react to the combo of early mornings and park days. Your normal energy level and sleep practices play a lot into how this will go for you. From being part of the 2014 and 2015 GSC/PHM threads there a lot of varying opinions. Some people say they don't go with families because they can't handle much time in the parks well along with the races, some feel they can handle both the race and family vacation aspect with little adjustment.
I have done GSC the last two years, and got up for the 5k both years as well, though I only ran it this year, I watched family the first year. Both years I toured with my active young kids each day. Both years I got to Orlando on Wednesday, and hit the expo Thursday after a morning in the park. I got up at 4 for the 5ks, 3-3:30 for the 10k and halves. I never stuck around after the races much, just got my medal, snacks, and pictures and headed back to the hotel for a shower and change. I took an ice bath after my first half in 2014, and really thought it helped, so I did it this year after the 10k and half. I also wore compression recovery socks all day after the races. Looks ridiculous, but I can absolutely tell a difference. I do it sometimes at home after long runs, and not on other days. I can feel a difference in my legs on the day after.
We were in a park around opening after the 5k and 10k, I joined them after my ice bath and shower after the halves, as they had gone straight to a park after meeting me at that finish. I do the 5k with my DD (now 7) and my sone and husband come watch. No one comes to the 10k, they sleep in that day -well DH watch me run by Bw from the balcony
Each day we hit one park in the morning, eat lunch there, hit a ride or two after lunch, then go back to the hotel (BLT in 2014, BWV in 2015) for pool time in the afternoon. Our dinners were all at other hotels so we did not return to parks again. So I felt like our vacation was not compromised by my participation in the races. My kids did not notice any difference from our regular days. In fact in 2014 when my daughter wanted to stay at Magic Kingdom after everyone else wanted to leave, I was the one who stayed with her.
However, I am an early morning person. I am also an early exerciser, so though the race mornings were earlier than normal for me, it wasn't a gigantic adjustment. In the main training season I am up by 5 most days. So if you are not used to early mornings, I suggest practicing by getting up at least an hour earlier than normal for a week or two prior to the races.
The GSC is so much fun. I swore last year was my last. I was never a runner, but I agreed to do it in 2014 with my sister, who then got pregnant. She deferred, so I did it again this year to do it with her. I said that would be it. But both years I have been fighting injuries, so I want one more try. Hoping third time will be a charm
I considered going with just the half this year, since its been the only problem race for me. But my extreme FOMO got me and I'll be in for the GSC and 5k with my daughter again.
