Transportation from Tokyo to Fujinomiya

My family and I will be visiting Japan in December. The main reason for the trip is to do a pilgrimage to Taiseki-ji, a Nichiren Shoshu Buddhist temple not far from Fujinomiya. I need help in finding information on transport from Tokyo to Fujinomiya, preferably by bus, as we were told trains are quite expensive. Any help/information is very much appreciated. Thank you.