Soup, about 6 gallons of each, might go 7-8 if you don't add salad and appetizers. This is more than 1 roaster each, they only hold about 3 1/2 to 4 gallons at a time, you need to plan to keep the extra hot on the stove or in the regular oven. Preheat roasters to 350, allow 2 hours covered, stirring thoroughly several times. Turn roasters to 180 when the soup reaches 165 in the middle. Be aware that 2 roasters will blow most household circuits, if you use an extension cord to reach a second circuit, it needs to be heavy duty, and taped down.

Yes, grilled cheese for this many is quite difficult and slow. On the other hand, cheese toast/bread is simple (if you have enough ovens) and delicious, and it holds better.

Grilled cheese discussion:
Here are great articles on the perfect grilled cheese:
www.closetcooking.com/2011/10/perfect-grilled-cheese-sandwich.html
www.huffingtonpost.com/2013/08/27/perfect-grilled-cheese-formula_n_3824935.html

Now, the basics:

2 ounces of cheese per sandwich and 2 pieces of bread- allow 1 sandwich per kid and 1 1/2 for adults.

Use a warm, not hot, griddle. Use a 200 degree oven to keep warm or to soften cheese. Cooking time depends on the cheese. American cheese slices will take less time to melt than harder cheese like cheddar, figure a minute or two on each side.
Cover, not tightly, to generate more heat to melt cheese, if you like it a bit soft.

The cheese
The kids will like a thick slice of American cheese
Dry, crumbly, fresh cheeses like goat cheese won't melt properly. Ditto for overly aged cheeses like a parmesan or hard Pecorino, or aged cheddar. For the true classic American style, nothing works better than ultra-gooey, not-too-sharp American cheese.
For grown ups, though, or serious eaters, a young cheddar, jack, gouda, Swiss-style cheeses like Gruyère (or its French cousin Comté), havarti, or young Italian and French cheeses like young Fontina, Tallegio, or Brie are great options.
The three usual optional add-ons are, thinly sliced tomato, very crisp bacon, or fine chopped tuna salad for a tuna melt.

Butter the outside of the bread, not the pan, and cover the whole slice. You can also use mayonnaise instead on the outside of the sandwich, this is a standard restaurant trick.

By the way, don't forget an assortment of great pickles and olives.

It occurred to me that if you are planning to cook them all yourself, more or less all at once, you might want to know about this method: Start trays of sandwiches in the oven, open-faced, then finish in a skillet. You'll get ooey, gooey cheese all the way through, plus nice and crispy toast.
so don't toast the bread first just put bread and cheese in oven first then on the grills.

This was advice for a lady doing soup and grilled cheese for just 25:

Get the types of breads that have an oval slice. I would suggest a seedless rye or pumpernickel, an artisan multigrain, a sourdough white (or possible Italian), and if you have access a fruit and raisin (cranberry walnut, for example. Get 1 slice white per person and 1/2 slice of three others, and add one extra loaf and you will come out great.

Cheeses; sharp cheddar of course, maybe a white? A Swiss, Jarlsburg, gruyere or Emmanthaler. A jack, havarti or fontina.

Very good to get sliced, if you buy at a deli. Allow 2 ounces per person plus some wiggle room. Might have thin sliced tomatoes and thin, crisp bacon prepared as add-ons; about 3 pounds tomatoes and 2 pounds bacon, and maybe a little deli-sliced shaved ham.

have 2 pounds of sour cream or plain greek yogurt and a pack of Goldfish crackers to float in the soup. Have a shaker of Parmesan cheese, or shaved Parmesan. About 2 gallons of wedding soup and 2 of tomato, and you may have some left.

And here is the discussion with a lady who wanted to do them using only the oven:
I am looking for a fast way to make 200 grilled cheese sandwiches using sheet trays. This is a very long process and i am looking for tips for making it faster.
ellen
09/22/09 If you really want grilled cheese, you can grill them ahead on the stove, refrigerate, and then reheat on the sheet pans. I would suggest you consider going with cheese toast instead.

If you do decide to do grilled cheese use a thin coating of mayo on the outside of the breads to give the crispy coating without having to deal with melted or softened butter, extra grease, etc. This old diner trick is faster.
ellen
09/22/09 Oh, here is the oven instruction:

Preheat oven thoroughly 20-30 minutes. Preheat oven to 450°F. Be sure oven is preheated to the right temp.
Lightly butter or mayo one side of each slice of bread.
Place on a cookie sheet butter side down.
Place your favorite brand of sliced cheese, 2 ounces/ slices per sandwich.
Place other piece of bread on top, butter/mayo side up.
Bake for approximately 6 minutes. Watch the time carefully, at 8 minutes they will be too done.
Take out of oven and flip.
Bake additional 3-6 minutes until done.

Crunchy outside, soft and cheesy inside, a very nice sandwich. Some possible additions; mustard, thin sliced ham, turkey, salami, avocado or tomato, tuna salad, sliced jalapenos

Here is my recipe for really good cheese/garlic toast, about half way down the page:

www.ellenskitchen.com/bigpots/meatballs25.html

Why You May Need an Appetizer Table
A self-catered buffet is a real challenge to the organizers, and things don't always come together as smoothly as hoped. By planning and setting up an appetizer area or "nibble table" which is ready when the guests begin to arrive, the cooks and servers have time to complete the arrangement of the dinner buffet. This is especially critical if there are children among the guests, or there is a wait before dinner, as at a wedding reception.

This does not have to be complicated. Three items, plus a punch, or two if one is alcoholic, are sufficient. Typically, include a fruit tray, a cheese tray and an attractive dip or spread; or you can go with a dinner theme such as TexMex with chips, salsas, Texas caviar and guacamole; Italian with bruschetta or antipasto; maybe shrimps or other cold seafood, if budget permits. For this menu, the classic relish tray would be one good choice, see the veggie tray page.

One appetizer service area serves about 100 guests.

If this saves you time, trouble, or money, please make a donation, maybe a dime per guest, to support this site. Thanks.

Don't just check outlets, check circuits; sometimes several outlets are on the same circuit.