Planing our trips is a fun part of the trip.
For our Alaska trips we needed to plan several
things beside the ferry part.
If you intend to visit Denali NP and want to stay at Teklanika cg
you need to make reservations it's a minimum 3 night stay and
you can't drive the road from there.The pass is only good to drive in and out.
On our trips we made reservations for all our nights stays at the 3 campgrounds
available to "truck" camp.
Most of the other camp spots we just drove up and camped.
If you are going to Homer there is a very nice/clean/convenient RV park just as you
enter the "town". We made a reservation there as well. I think the only other place to
spend some nights is the crowded place out on the strand.Don't recommend that one.
At the end of the TWH at the Yukon river across from Dawson City there is a nice campground
and a free ferry across the river.
Hope some of this info gives you some ideas.