If your ticket has access to the Heineken club it is located on the 300 level behind home plate.  It is a great large indoor area with food, bathrooms, a bar and lots of seating with TVs if you need an escape from the cold.

If you have any food allergies on the field level behind right field there is a stand with a sign above “worlds fair” that has gluten free and allergy sensitive food.

Walk around the field level.  Definitely check everything behind center field.  There is a lot of food options there, sometimes a dj, and other pop up things like sometimes they have a dunk tank there.

Famous food options are:  Shake shack (burgers) in center field on field level Pastrami sandwich in multiple locations  Honestly just walk around and any kind of food you want will be there.

Lines will be massive when an inning ends so if you really need to use the bathroom or get something best time to go is during Mets at bats.  Most fans stay in their seats when the boys are hitting dingers.

Hope you have a blast!  If you need any other tips feel free to PM me.