Start with a large round of sour dough bread cut in half and the center scopped out part way to make way for fillings.

filling 1

Italian cold cuts, sliced roasted red peppers, thin cut red onion, Provolae cheese, chopped lettuce and tomoto. Make the evening before . Wrap tightly in foil and cut into serving pieces at the picnic site.

Other fillings

Italian Tuna, Ripe diced tomatos, capers, red wine vinegar and olive oil. Assemble as above, but use individual crusty rolls, wrapped well in foil

Given that size crowd, why would you want to spend time making sandwiches ahead of time?

I would pack a selection of fillings (ranging from cold cuts to potted shrimp) and breads, then let each person assemble their own. Easier on you, better for them.

This should fit the bill for one selection:
PICNIC SANDWICH
One 1 lb loaf frozen bread dough
4 oz thinly sliced cooked ham
4 oz thinly sliced cotto salami
4 oz thinly sliced pickle & pimiento loaf or other lunchmeat
8 oz ricotta cheese
6 oz provolone or Monterey Jack, shredded coarsely
1 medium onion, chopped
1/2 cup chopped green bell pepper
1/2 cup chopped red bell pepper
1 tsp dried oregano
1 egg beaten with 1 TBL water, optional
Sesame seeds or poppy seeds, optional

Let dough thaw to room temperature. Preheat oven to 350°. Cut the meats into 1/4" wide strips. Mix the meats, cheeses, onion, chopped peppers & oregano.
On a lightly floured surface, roll the dough to a 10x14" rectangle. Place the dough on a lightly greased baking sheet. Spread the filling over the center third of the dough. Bring the edges to the center & seal.
Turn the dough seam side down. make slits on top of the loaf. If desired, brush w/egg wash & sprinkle w/sesame or poppy seeds. Place in oven immediately & bake 25 minutes or until golden brown. Cool on a rack to ensure a crispy bottom.~~Great Beginnings, Grand Finales(Can make the night before & bake the next morning.)

This is similar to Bonelady's.
MUFFALETTA (serves 8-10)
1 loaf round bread, 8-9" diameter
1/4 lb sliced mortadella or summer sausage
1/4 lb sliced Italian hard salami
1/2 lb sliced Mozzarella
Shredded romaine
3 tomatoes, sliced

Olive salad:
1 cup pimiento-stuffed green olives, chopped
1 cup pitted black olives, chopped
2/3 cup olive oil
4 oz jar diced pimientos
5 TBL chopped Italian parsley
2 anchovies, mashed (I omit)
1 TBL chopped garlic
2 TCL chopped fresh oregano
2 tsp lemon juice
Pepper to taste

A day or 2 ahead, make the olive salad by combining all ingredients in order given. Store in refrigerator. Day of serving, cut bread in half horizontally. Remove all but 3/4" of soft bread from inside. Drain olive salad, reserving the dressing.. Use dressing to brush inside of loaf, top & bottom. Put 1/2 the olive salad into the bottom of the loaf. Add layer of lettuce & layer of tomato. Layer 1/2 the meats & cheese. Repeat w/remaining meats & cheese. Place rest of lettuce & tomato on cheese. Top w/remaining olive salad. Put top on loaf. Wrap securely in plastic wrap.
Cover with a small plate, weighted down with several unopened cans. Refrigerate until ready to use, at least one hour. To serve, cut into wedges.
You can use different meats, cheeses & bread. Also good with caraway rye.~~Fare to Remember

This is a favorite of ours.............

SO LONG SUB
(from Linda in Tennessee)

The bread you hollow out to make room for the robust meat-and-cheese filling is great for making salad croutons.
Source: Better Homes and Gardens

1/3 cup chopped fresh basil leaves
2 tablespoons olive oil
1 tablespoon balsamic vinegar or white wine vinegar
1 8-ounce or 1/2 of a 16-ounce loaf unsliced French bread
6 ounces thinly sliced mozzarella cheese
4 to 6 ounces thinly sliced lean pastrami
2 plum tomatoes, thinly sliced lengthwise
1/8 teaspoon cracked black pepper

1. In a small bowl, combine basil, oil, and vinegar; set aside.
2. Slice bread in half lengthwise. Using a spoon, hollow out bottom half, leaving a 1/2-inch-thick shell. In the shell layer half the cheese, all the pastrami, and all the tomatoes.
Top with basil mixture; sprinkle with pepper. Top with remaining cheese and bread top. Wrap in heavy foil. Transport in an insulated cooler with ice packs.
Makes 4 to 6 main-dish servings.

You can change this one up by using, minced ham or canned crab, or salmon. I often make three different types so everyone has a choice.

Stuffed Baguettes

1 Baguette or French stick
2 cups spinach leaves choped and packed
4 oz cream cheese room temp
1/4 cup fresh dill chopped
1 TBSP milk
4 cups minced ham
1/3 cup toasted pistachions chopped (optional)
1 TBSP dijon mustard
1/3 cup mayonnaise

Slice the baguette lengthwise. Hollow out the bread leaving the shell about 1/2 inch thick. Rinse spinach and shake off excess moisture cook in just a bit of water until the leaves are wilted. Drain and squeeze dry and chopp in the food processor ( I just use frozen and ensure it is well drained). Combine cream cheese , dill , milk, and spinach until spreadable. Combine ham, nuts, mustard and enough mayo to make a moist filling. Spread cream cheese all over the inside of the shells. Spoon the ham mixture into the bottom shell, mounding slightly. Place top of loaf back over the filling.
Wrap tightly in plastic wrap. Refrigerate for at least 2 hours and as long as 8. Serve cut in slices.

Here is another Muffuletta recipe. Excellent and can be made the day before. SOunds harder than it is.

Real N'awlins Muffuletta (Weed)

1 Cup pimento-stuffed green olives crushed
1/2 Cup drained kalamata olives crushed
2 Clove garlic minced
1/4 Cup roughly chopped pickled cauliflower
2 Tbl drained capers
1 Tbl chopped celery
1 Tbl chopped carrot
1/2 Cup pepperoncini drained
1/4 Cup marinated cocktail onions
1/2 Tsp celery seed
1 Tsp dried oregano
1 Tsp dried basil
3/4 Tsp ground black pepper
1/4 Cup red wine vinegar
1/2 Cup olive oil
1/4 Cup canola oil
2 (1 pound) loaves Italian bread
8 ounces thinly sliced Genoa salami
8 ounces thinly sliced cooked ham
8 ounces sliced mortadella orcappicola
8 ounces sliced mozzarella cheese
8 ounces sliced provolone cheese

Directions
1. To Make Olive Salad: In a medium bowl, combine the~
green olives, kalamata olives, garlic, cauliflower, capers,
Jcelery, carrot, pepperoncini, cocktail onions, celery seed,
oregano, basil, black pepper, vinegar, olive oil and canola
oil. Mix together and transfer mixture into a glass jar (or
other nonreactive container). If needed, pour in more oil to cover.
Cover jar or container and refrigerate at least overnight.
2. To Make Sandwiches: Cut loaves of bread in half~
horizontally; hollow out some of the excess bread to make room for filling. Spread each piece of bread with equal amounts olive salad, including oil.
Layer 'bottom half' of each loaf with 1/2 of the salami, ham, mortadella, mozzarella and Provolone. Replace 'top half' on each loaf and cut sandwich into quarters.
3 Serve immediately, or wrap tightly and refrigerate for a few hours; this will allow for the flavors to mingle and the olive salad to soak into the bread.

Oh my goodness! These all sound fabulous! I thank you all for the wonderful ideas. In time, they will all be tried.

Geri

Ginger, thanks for posting the Muffaletta recipe. Now I know who to thank. I've been making that for years, but when I first started copy/pasting recipes I didn't think to add the name of the poster. That sandwich is to die for and I thank you from the bottom of my heart! (You've made many guests happy campers!)

I had pretty much the same question posted here, and got the same recipes. I'm going to make three of them.

My reason for making these ahead of time is that 27 of us will be in a cabin for three days and I was assigned lunch for Saturday. There is only one fridge! Moreover, there are six women responsible for the food, and I've never known a kitchen big enough to accommodate six women except when it's a church dinner. LOL.

Thanks again everyone.