Polarize isn't needed but will be a good addition when you want to cut down glare and turn the sky blue instead of white (or use GND filter).
You may need to over expose the scenery from +1/2 to +2.5 stops. Hence it is best to use spot meter to read the highlighted area and the shadow area and average that to get your shot (in manual mode or use exposure compensation. The scene may require more than 5 stops that is beyond the ability of the sensor to capture, therefor you may need to employ HDR technique (and/or master dogging and burning technique). Or, simply over expose the shot by +2 stops as suggested above and push/pull process in Lightroom to recover the shot in RAW mode with dogging/burning processing.