Restrict the king with your rook and bring your king closer.
Use the rook to cut off part of the board. Bring your king closer to help drive the enemy king toward an edge, then check along that edge. Keep the rook safe and avoid leaving the opponent with no legal move when it is not in check.
Cover the king’s escape squares
Your king covers escape squares beside the enemy king. With those escapes covered, your rook now threatens checkmate.
2 more clean runs (at any point) to reach Recall.