Are there a standard departure times? How long would a person have to wait if they just showed up?

They can see you pull up from either side so usually only a short wait

Everyone is very right

Less than 30 usually

Give or take 20 to 30 minutes

They cross as needed when a car arrives at the landing dock. You may have a short wait. You may get lucky.

Depends on what side of the river they are on. 15-20 minutes top.

I have watched them a few times while walking over in the area. The only time I have seen them cross the river is to take someone across. So, I believe it's as needed and not scheduled.