Joanne,
Thanks for asking your question to planDisney!
Yes, you can absolutely 
park your car at the Transportation & Ticket Center, even if you do not have an active Theme Park Reservation for the 
Magic Kingdom. Once you park, you can hop on the 
monorail as you head to your dining adventure!
I will admit, my daughters and I will fabricate almost any reason to go on another monorail ride! It is an attraction unto itself. I would hate, however, to neglect to mention that if you have a dining reservation for a restaurant at 
Disney’s Grand Floridian Resort & Spa, you can park there as well. This would save you some money, and you could still take a pre- or post-meal ride on the monorail. Neither of these options would require a Theme Park Reservation for the Magic Kingdom. 
BONUS TIPIf you happen to arrive early for a dinner date, consider dropping into the 
Enchanted Rose on the 2nd floor of the Grand Floridian Resort lobby. This elegant lounge is perfect for a drink and appetizer before your meal. 
Please feel free to 
write me back directly if you have any follow-up questions.
Have a Magical Vacation!Doug