Most produce is easily frozen. Except produce that isn't. Most any fruit that's relatively firm (rhubarb, strawberries) should be washed, sliced into pieces the size you'd like to eat (if necessary), and then laid out on a cookie sheet and frozen. Writer Katie Goodman does a nice job of illustrating the process on the Craftzine blog.
Juicy produce like peaches, tomatoes, and plums needs a little special care. Stone fruit needs to be stabilized in a sugar syrup; tomatoes should be skinned and seeded before they are frozen. Most vegetables, like peas, need to be blanched and shocked before freezing. Whatever you end up putting up in your freezer will taste much better and fresher than the frozen produce you buy at the grocery store.
Many herbs freeze beautifully and can be made into little cubes to pop into sauces and soups.
Rice and Grains
Most freeze well. If possible, undercook a bit before freezing in zip-top bags in individual portion sizes. Cooks on the Chowhound boards advise that smacking the bag around on the counter before microwaving will separate the contents into grains. Feels good, too!
Eggs can be frozen, but not in the shell. And you must separate out the yolks and the whites and add either a bit of salt or sugar to the yolks before freezing or they'll get lumpy and weird. "If you try this, make sure you label the container clearly, so that four months from now you know whether you are supposed to be making custard or hollandaise," suggests one commenter on Chowhound. Butter and buttermilk freezes well, as does milk, in cubes or in plastic containers.
Yogurt, cream, and sour cream tend to separate when frozen and thawed. Eat it up before you go on your trip.
Making your own baby food and freezing it into cubes is a snap, and just about any sauce or soup without a lot of cream, yogurt, or sour cream in it also freezes well. Many people think some dishes, like chili and spaghetti sauce, taste better after a trip through the freezer. But dishes or soups with a lot of pasta or potatoes in them may become grainy and mushy.
Every time you make meatballs, dumplings, cabbage rolls, or other small individual items, thinking about making a double batch. Frozen on cookie sheets and packed into the ol' zip-top bag, they'll make a quick supper some other night.
Pound cake can actually improve from being frozen. Cookie dough freezes well: Roll it into balls on cookie sheets, freeze, and then store in bags or plastic-ware.