I’ve done the rope drop in July and thought the same thing
We queued on arrival at the park to get through security (that took 20 mins)
We queued to then get through turnstiles (that only took 5 mins)
We then queued to get to the left of th park towards pandora world (that took 10 mins)
We then tried to get to FOP asap (we weren’t allowed to run)
We then had to queue to join the real queue of FOP (that took 30 mins)
We then joined the real queue that said 60 mins (but only took 30 mins)
We arrived at the park at 7.40am (it was early opening for hotel guests at 8am that day) and due to the various queues we got on the ride at 9.15am
The argument other people give is that you still have a full day for the rest of the park which is of course valid
Ideally the best way to do FOP is with a fastpass and then you could enter AK just after opening once rope drop queues have gone and go and do the other rides whilst everyone storms pandora world
I really wouldn’t worry about navi river if it’s not easy to fit in - its good but not great. The queue for that ride was tedious and slow as well
You will rather do FOP twice or three times!!