I just looked up the notes I jotted down
Can't copy and paste because the Chinese characters all garbled up when doing the paste on this site.
The nicest views are in the Lower Lake and the biggest fall is in the Lower Lake. The trails also are easier. Upper Lake has more falls but the trails are longer and more ups and downs.
I would go to Entrance No.1 and get the postcard view done first thing, before the rest of activities. You should get in the park as early as you can. When weather is good, the view is ruined by People Mountain People Sea on the broadwalk, it is not beautiful at all, at least to me. So we were sort of glad that the day we went the broadwalks were closed so only the Natural Beauty is in front of us, NOT a soul can get on the broadwalks.
Briefly, use Entrance No.1 when weather is good you can do the following - go down to the bottom of the valley, used the floating bridge to the other side of the river. Follow the broadwalk, you then get to the bottom of the Great Fall. You will see a stoned path going up to the No.7 View Point. That is where you will get the Full View of the Postcard View.
If they close the floating bridge (on the day we visited), you can still walk upslope on the path at the side you enter the park, there would not be nice viewing platform but along the way you still get to see the postcard view, albeit not as complete as at the No.7 viewing platform on the other side of the river. That was how we did it.
It was in May, so the lake district was fairly rainy. Yet there were still A Ton of People around. At the time lodging was hard to find, needed to book very very early, I mean months early. After these years I am sure the options are very much expanded, and then the effect on Pandemic, causing the Chinese could not come - this may ease the situation a lot.