Advice please! I picked 15 + gallons of apples from trees at a friend's house. The varieties are unknown. My friends eat a few fresh but do not process any. Everyone seems to like them for eating apples - they are crisp, juicy, nice size. But I think the flavor is quite bland. I prefer a REALLY tart, crisp and juicy apple and these are not tart at all, and seem to be lacking in flavor. I don't have any experience with this type of apple.

So.... what to do with these? If the flavor is not great now, is there anything I can do, or add to them, to make them acceptable after processing?
Would you consider mixing another fruit (cranberry, pear, plum, etc) to make fruit juice, leather, applesauce, etc? What, if anything, have you done in the past with the "less tasty" apples?