Lynzee,
Thanks for the question!
So the basics of a ticket, when it does not have a park hopper, is that you can go to just one park for any given day. If you enter the
Magic Kingdom in the morning, for the rest of that day that is the only park you can go in to. You could leave, re-enter, and leave and re-enter again numerous times, if you so desired. What you cannot do is go over to, say,
Epcot, and go in that day.
So if I understand your question correctly, the answer is a solid
YES! You could go in to the Magic Kingdom in the morning, have some fun, ride some rides, and enjoy yourselves. You could then go to your resort hotel for a nap (my preference) or some pool time (my daughter's preference), and then off to dinner at
Chef Mickey's. Then you could go back in to the Magic Kingdom for more fun and fireworks!
The ONLY caveat is that if the park is super full (like Christmas Day, New Year's Eve, etc.), you may not be able to get back in, due to capacity issues. But that is very uncommon, so I would not let it concern you!
I hope this answers your question? If not, write me back and I would be glad to clarify!
Have a Magical Vacation!