One day trip to Nikko, plan of attack?

I can spend one day (about 9/10 am - 7/8pm) in Nikko. I want to see the major shrines and temples, of course. Toshogu, Taiyuinbyo, Rinnoji Temple, Futarasan Shrine, Kanmangafuchi Abyss, Shinkyo Bridge and maybe one or both of the waterfalls. I don't have to see everything, but that is a general idea of the places I would want to hit.

I don't think I would have the time to visit an Onsen or anything, but maybe.

Looking at the map, it seems the sites to see in Nikko are almost a straight line and back from Nikko station.

I am basically asking for simple pointers from anyone who has done a day trip. How to divide your time, what is 'must-see' and what path did you take?

Such as, the cheapest or alternatively the fastest way from Shinjuku. Should I buy one, or any of the offered foreigner passes? Would you suggest a bit more pricey guided tour?

Thanks for your help.

Way too much to see in that time. Pare it down to a max of 2 shrines and a falls. Even that may not be possible.