Hey Nicholas! I actually used apples last year:
I took about 5lbs apples straight from the orchard, peeled, froze, thawed, then added the "sauce" to the secondary (the freeze/thaw pretty much "sauced" the apples for me). I started with the popular Caramal Cream Ale recipe, which always resurfaces around here, as the base beer in attempts to make a "caramel apple" beer of sorts. I used a sweeter variety of apple, as i thought a sour one would overpower the base beer itselfe, and i used a neutral yeast & minimal hops to allow for the apple to come through.
People really enjoyed it, as did i, but the apple didn't come through nearly as much as i wanted it to. It was really only present in the aroma. Things could change, though, if you used the apple during primary fermentation, but my main concern would be the clove & typical hefeweizen flavors overpowering any traces of the apple.