I freeze pie fillings (if you put your ziploc bag of filling inside a pie tin lined with a dishtowel, you'll have it frozen in its end-use shape as well.) My grandmother-in-law entrusted her cookbook collection to me, clearly the most beloved of which was the Farm Journal's Complete Pie Cookbook (the original 1965 edition)
Frozen apple pie filling: 1 quart apples, 3/4 to 1 cup of sugar, 3 tbsp quick-cooking tapioca, 1/4 tsp salt and seasonings of your choice and 1-2 tbsp lemon juice. Fold ingredients until combined. Line pie pan with towel (you're trying to imitate the thickness of your piecrust here) and top with heavy-duty aluminum foil and then saran wrap, extended over the edge to cover (I use a ziploc freezer bag) cover, insert filling, seal and freeze. To use, unwrap, place in pastry lined pan, dot with 1 1/2 tbsp butter, top with lattice or vented top crust, and bake at 425 for 1 hour.
Or here's their cranberry-apple, which uses flour as a thickener (which I prefer)
3 cups sliced apples
2 cups fresh cranberries
1 3/4 cup sugar
1/4 cup flour
1 tsp cinnamon
1 1/2 tsp melted butter
Freeze and use as directed above.
If your apples are frozen, I'd be careful to do this quickly so they don't thaw and refreeze if you can; you're probably going to lose some moisture along the way...