Okay, I see now.
The length of the sense traces from Rsense to the CS pins is not very critical, since those pins are high impedance. What is critical is the loop formed by the input bypass capacitor, Rsense, the catch diode, and the ground plane. That loop must be kept as small as possible since it must carry discontinuous currents. For good gate drive, the loops formed with the ground and Vin pins of the chip and the gate drive pins should also be kept small. For Fsw of 100KHz, a couple inches of length is a lot, but what it really comes down to is loop area. IMO you should try to keep all of those critical loops to be maybe one or two square centimeters at most.