Ok I'll take a look at that :)
I'm using systems, and one of them is a CheckpointSystem which keeps track of the reference of the last checkpoint. It has an accessible reference to the last checkpoint, and it gets updated everytime you enter a checkpoint trigger. In addition to that it also keeps track of every object that has yet to be used and updates their visiblity once you get teleported back to the last checkpoint.
Hopefully that helps!