Hi Sara! First off, thank your service member for their dedication and service to our country! As an Air Force wife, I completely understand the trials and all around sacrifices that come with the territory of loving someone who serves. That's why I just love and appreciate so much that Disney offers this wonderful token of their appreciation to members of the Armed Forces.
I have good news - yes, you can absolutely use a few days here and then later a few days there to break up your tickets into two small vacations. (So
buy the five day ticket option and stay an extra day!) You are correct that the 14-day stipulation is for non-military tickets. And we're in luck this year as there are no blackout dates that have traditionally fallen in April. Just be sure to note that the last day these tickets can be used is December 19, 2018.
Depending on when you come back in the fall you should check out Mickey's Not So Scary Halloween Party or Mickey's Very Merry Christmas Party. Both are special ticket events that happen in the evening after Magic Kingdom Park have closed for the day, and both offer a military discount. If you're unable to attend either of those, try to make your second visit during
Epcot's International Food and Wine Festival. Special concerts, kitchen demonstrations, but what makes this festival so fun is the addition of over 20 more food and drink kiosks that represent nations only seen at Epcot during this special time of year.
I do hope that you have so much fun during BOTH of your trips to Walt Disney World Resort, Sara, and again, Thank you!
~Kristen