At large bed/linnen/kitchen supply stores they sell relatively inexpensive sets of glass corningwear caserole dishes with rubber lids in multiple sizes. These work really well for freezing dishes in (i freeze both cooked and uncooked meals this way) and i haven't had freezer burn problems. I am then able to easily put a compiled dish straight from the freezer to oven (though i usually put the cool glass dish into a cool oven - or microwave is also an option if you prefer). The rubber lids help them stack nicely in the freezer too.
If you don't want to buy lots of these dishes but one set, freeze things in them and once frozen solid, the transfer them to freezer-safe gallon plastic bags and store those in the freezer and re-use the glass dishes for something else (this is also a good way to give a frozen meal to a friend so you don't have to worry about getting a dish back). A 9x9 or smaller size works well for this. they also have gargantuous ziploc bags at the grocery store (though don't know if they're good for freezing) if you wanted to use them for a larger caserole size.
It doesn't have to be a caserole, it could be soup, lentils, etc.