It is White Pass summit. But, this is hardly the highlight of the area, and photos from the train are actually excellent and superior as the road is less scenic.
NOT sure where you got some of your "information" but it is not accurate, there is NO "park fee", NO "parking fee". By road, you just pull over, simple. A rental car would offer you a Lot of photography opportunities. I too find Murray's Guide, "necessary".
As for your cruisetour- I again, suggest, you dump the included Denali tour, Princess gives refunds-- TAKE advantage of it, and get yourself on a shuttle bus. Hopefully you have 2 nights there at the Denali Princess? My min. distance in is Eielson. If you haven't, educate yourself on what Denali is all about, www.nps.gov/dena
It would be well worth your while to go in twice, which can be done- IF YOU want to take advantage and make the effort in planning.
Hopefully you also have the Kenai Princess in your itinerary? Spending the money for a Kenai Fjords boat tour, is a photographer's dream, loaded with significant scenery and varied wildlife.