Five-cell route: POWER
Trace POWER through 1 at row 4, column 4; 2 at row 5, column 4; 3 at row 5, column 3; 4 at row 4, column 3; 5 at row 3, column 3. Reading those cells in order gives P → O → W → E → R.
Go down once, left once, then up twice. The route turns two times and forms three straight segments while spanning three rows and two columns. Once these five cells are assigned, 40 open cells remain for the five longer entries.