Goes together well with the Easy Victory, Chief's Food, and Teleporter skills in the same skill tree. You can force mice to get the cheese and enter the hole by placing an apple near them and then teleporting them to the cheese, and then the hole.
Also goes together well with the Personal Teleporter skill in the same skill tree, allowing you to place a checkpoint anywhere on the map to teleport to.
It's better to make apples transparent so that the mice cannot push the apple off and ruin your plans, but in some cases, if the mice play along, you can place solid apples to help the mice reach high places.
If there is a small hole in the map or your build, you can place a solid apple to cover it since apples are so small.