Collin,
Thanks for your question to planDisney!
Yes, you can use one of your ticket days to visit a theme park on your arrival day as well as on your departure day. When my family visits Walt Disney World we try to get evening flights home so we can squeeze out that last little dose of magic before heading home by going to the
Magic Kingdom Park on our departure day.
Basically, after checking out of the resort and dropping our bags off at the resort hotel's Bell Services desk for safe keeping, we will head to the park in search of the perfect souvenir and a quick counter service lunch. We always return to our most nostalgic and iconic family attractions, including
"it's a small world",
The Barnstormer, and my personal favorite,
Walt Disney's Enchanted Tiki Room.
BONUS TIPIf you are flying home, know that most shuttle services will schedule a pickup time 3 hours before your flight departure. So plan your transportation back to your resort hotel from the parks accordingly.
Have a Magical Vacation!
Doug