maybe on overlap you snap the player to one of the token.
To select the proper token you can have a tiny sprite detector, or compare Y position of player and rope token.
To climb the rope, probably a lerp between Y position of two adjacent token
To swing, apply an impulse on the token your aformentionned detector is on (if there's two, pick one at random :D) on key pressed.
No sure if all that will work but it's my first ideas