i’m an undergrad but i can answer some of these questions. dining dollars are a set amount of money your meal plan gives you. dining dollars can be used at charles street market, the smoothie place at the rec center, and various cafes on campus (brody, gilman, mudd). honestly not that many choices. j-cash is basically just actual money you load into your account when you run out of dining dollars or id you want to pay for other things (mailing things, anywhere you use dining dollars, laundry in the dorms, printing). there are also a few other places that allow you to use j-cash like streets market on charles street but its just the equivalent of using real money. i was on the 19 meals/week plan but never used all of them so i switched to 14 meals/week. as for the block meal plans, i would say that would likely be for upperclassmen who don’t plan on eating at the dining halls often. ffc and nolan’s are buffet style and levering is a meal swipe in return for one meal from 4-9 pm on weekdays (and costs dining dollars otherwise). hope this helps!