Could also connect a bunch of locks and put all the keys on a key ring. Lots of pictures of latch, lock, etc ideas for montessori type preschool. This lock one could be made with 2 boards, some o-rings, and some locks from Dollar Store.
This word building activity travel kit is perfect for toddlers and preschoolers for road trips and long car rides and you can customize it with sight words, color words, word families, or whatever your child is currently learning. Great for a summer learn