I am considering going up to Kawaguchiko 5th station, is this a worthwhile trip if I do not plan to climb Mt Fuji?I personally don't think it is worth. But if you have an urge to ascend the mountain, it might be worth for yourself. The views of Mount Fuji are more spectacular than the views from it.
Also what are the best things to do in Kawaguchiko?
It depends on your personal interests. Here are some details:
http://www.japan-guide.com/e/e6900.html
Is it easy to get around the area on foot?
No. Many places are too far to reach on foot. I recommend bus, rental car or bicycle.
I would also like to stay for the sunset, does anyone know approximately what time the sun will set?
Shortly after 5pm.