Hi Melissa,
I love Mickey's No So Scary Halloween Party (MNSSHP). I have toured both on and off the Disney Dining Plan. Each time I toured I looked at my vacation and where I was going to dine to determine if the Disney Dining plan was going to be worth it to my family. I will say that when my children were under 9, it was easier to go with the dining plan because it was less expensive to feed them on the plan than off. Once they became "adults", I had to weigh the two options. Here is how I recommend you look at deciding:
First, how many in your party are under 9? If more than half, I would lean towards the plan. Second, how do you eat when touring? We usually eat breakfast in the room with food from home, quick service lunch and then eat at a table service for dinner. This makes the basic dining plan a good option for us. Third, how much does your family eat during a meal? The dining plan allows fixed costs when you add up appetizers and desserts. My family rarely eats both so the basic dining plan works for us. Finally, are you going to character meals or signature restaurants? These alone mean a lean towards the dining plan because those meals are about half the cost of a meal for a day. Plus a refillable mug will save on drinks at your resort.
I would look up menus at restaurants you are planning on eating at AllEarsNet.com to get a price idea for a meal. I would then call Disney at 407-WDW-DINE for a price on the plan. Or you could calculate online the price of the trip with the dining plan and without.
Wishing you a magically spooky vacation!
Beth